I didn't notice any other successful ways of controlling the wizards power that brings the wizard into line with the rest of the party from the discussion. If people could present such tactics and options, I would be very grateful (I'll spam XP to everyone

) as I'm presently having to deal with exactly this situation (an 18th level wizard running rampant over his 17th to 20th level peers). I'd like to think I have a modicum of intelligence and that I'm conversant enough in high level play but in this regard, I seem to suck (or perhaps there is no reasonable way and I just need to accept the wizard's power over the rest of the party).
I'd be happy to try and help....but I think the point that the players in my group usually haven't been optimizers means they're likely not the guys you're looking for advice from
I've explained some of the things I've done, and they're spread out through the thread.
Here are some others:
1-Work your game so the 15 minute workday isn't an issue. Use timelines. Conflicting NPCs with goals that differ from those of the PCs. Make there be real consequences for not attending to quest issues in a timely fashion. Maybe there's an organization that is working against the PC's goals, and they want the same McGuffin the PCs want. When the PCs take out the gatehouse encounter, and then leave in order to rest and rememorize and go after the big baddy, their arch enemies from the other organization come in, now that the PCs have so nicely cleared out that gatehouse encounter, and do something to disable or kill the big baddy and steal the McGuffin.
2-Have enemies work smart. If the wizard is the tactical nuke of the party, what defenses would the NPCs use against them? Antimagic shell on a fighter/wizard works really well. But mainly, recognizing that the wizard can be dangerous, and has to be a priority.
3-Sometimes (at least at lower levels) simple measures like using caltrops, or marbles can work wonders. A rogue in our party was renowned for carrying bags of marbles, and scattering them all over the floor under the feet of her enemies, forcing saves to avoid falling flat on the ground. DR doesn't protect against it, nor does mirror image if it's an area attack....nor does mind blank or spell resistance, etc. A simple fly spell would work, or levitate..if the wizard had them.
4-Use spellcasters against your spellcaster. They'll have tactics to deal with him.
5-Dimensional Anchor could often be another good one. It allows a save, sure, but sometimes it could keep that wizard from getting away.
6-Mind Fog, followed by Confusion was often a good combo......depending on whether Mind Blank was already active or not.
Also.....any spell or effect that could occupy the other party members who don't have all these magical protections (like Mind Fog + Confusion) or Black Tentacles, Solid Fog, or a host of other mid level spells could limit the wizard's companions' ability to protect him. While they're busy trying to get untangled or whatever, the butchers move in to take down the mage.
Beyond that, the biggest thing is just not to give the wizard time and space to work. Even when protected by potent defenses like Moment of Prescience and Stoneskin, just how much protection they can offer can be limited.
The wizard is 1d4 hp/lvl. Thus, counting max hp at lvl 1, the average wizard will have 52 hp at lvl 20....plus whatever he gets from high CON or whatever. If he's put most of his points in INT, or, say, 3 in INT and 2 in CON, maybe he's got...what...13 or 14 CON? If he's using an ability buffer spell, he might have +4 to his CON..thus 17 or 18. So, now we're talking, buffed, 112 to 132 hp. Throw False Life on top of that... Moment of Prescience might protect against the one attack. But after that, Stoneskin is relatively limited in utility. DR 10/adamantine. Great. But at level 20, you've got fighters who might have.......+4 Flaming Burst Longsword, with 30 STR (due to level enhancements, buffs, specialization, maybe a girdle), who can cause 1d8+10+4+2+1d6 dmg (and this description is not even really optimized in the first place....but my dog is crying to be let out of the kennel, so I can't spend an hour researching a more indepth post). I don't have my books in front of me, so I know it's possible to do even more than that......the longsword isn't even the most damage optimized weapon. Because the Wiz' AC is relatively low in comparison to that of other characters, the fighters could conceivably hit with multiple attacks. Low level mooks with bows can pound multiple missile attacks at the wizard to wear down things like mirror images and stoneskin spells. A rogue spamming the trip attack and flanking the wizard can make casting spells very difficult.
If you use optional books, the wizards' options get better...but so do the options available to everyone else....then you get the mage killer feats etc. that restrict his ability to cast defensively etc.
I used to get frustrated at how easily characters of other classes could destroy wizard NPCs I threw against them. It comes down to things like if the wizard has his buffs up at the start of the encounter, if he has initiative, or if he's always acting later in a round, if he has ways of slowing down the ability of other characters to get in close to him etc.
At the end of the day, what I saw happen with wizards was symptomatic of what I've observed with high level play, period. Initiative matters. Those who got the jump, and got the first good hits in often carried the encounter, as attacks became powerful enough that if you had the third action in a round, you could be down to 50% of your hp in the first round after a few bad rolls...and then your whole strategy changes. Whether it was fighters, rogues, druids, wizards, or something else, I've seen all of these classes dominate games at various times. Sometimes it depends on the luck of the dice, timing, initiative, and the whole paper/scissors/rock aspect as to what you do vs. what the opponent chooses to do in a particular round.
There was another spell in an optional source, based upon one I saw in 2nd Ed. in a book about schools of magic....it was basically a scrying defense spell...if someone scries you, or tries to look at you with a magical sensor, they get hit with a nasty attack that goes back through the scrying link and fry the caster. Sort of like what Murmandamus did in A Darkness at Sethanon. I'm pretty sure somebody ported that spell over to 3E, but I can't remember which book it was in. I never did use it, but it could be something to help. And if it makes the wizard think twice about scrying, and rely on the rogue's sneaking talents instead, well, you're creating more reason for the party to work together, instead of it being the wizard's show, with everyone else being his support.
I'm not denying the wizard is powerful. I'm just saying that a good player can make *any* character powerful. Well, almost any character

That kender bard (Planescape) was not the most effective....but it was a roleplaying player who ran him, rather than rollplaying....so it didn't matter.
Different games. What worked for me very well might not work for you. I could try running in your game, and find myself just as stumped by your players as you've been.
I'm not going to say that my way is better....just that it seems my game went differently than yours, and these problems didn't arise.....but it could be as simple a thing as that my players didn't care to optimize. Maybe we're more casual. Since I'm not an optimizer, I'm likely not even the right one to ask. But I'm sure if you ask on the CharOp boards, you'll find people can give you all kinds of ideas.
One note....you used the example of Spell Resistance being a good defensive spell...but it's a cleric spell. In my game, the characters didn't put all their efforts into just buffing the mage. Usually the cleric used that one on himself, or on the fighter, to give the fighter some protection so he wouldn't be neutralized by the first Dominate Person used against him (for instance). But for that matter, if any character in the party was the focus of all of the buffing efforts of the spellcasters, he would be difficult to deal with.
Banshee