I am not a mathematician sorry- nor do I have enough information to even say that a spell like Bear's Endurance even makes it into the game. It is a rather iconic spell though so let's imagine it does. Would you not then agree that what I posted, given it only includes one brief reading of the basic rules, constitues slightly more than 'not a single example'?
Bless gives you +1d4 to all saves while active, to at least 3 pcs (more if you cast it as a second level or higher spell). So if you bust out an inspiration point when you get nailed with 'Disintegrate' (probably not a bad time to use something like that, agreed): You get to roll 2d20 and keep highest roll + 1d4 to your save. That is a greater increase of +5% CHANCE (even I can figure that out).
Then let's assume Bear's Endurance is an available possibility: say CON gets a +4 boost which equates to a +2 bonus if it is similar to existing versions in other editions. Now your CON save is 2d20+2+1d4. Seems like the weakly wizard has a shot of surviving Disintegrate to me. Will potions/wands/staves be able to replicate this effect? We don't know.
Yes, your cleric could have his/her concentration broken... lots of things could happen. Couldn't your fighter get to the other wizard first before Disintegrate becomes an issue? Maybe. Could your wizard drop a Silence Spell on the area first?
All I am wanting to add to the conversation is the opinion that (with very very limited knowledge of the rules), it at least appears to be potential ways to overcome character weakness, and more options may become apparent when we see additional features added with alternate rule options, more spells, and magic items (and maybe feats?).
For the record, I also
Sorry, didn't mean so much "examples" as "scenarios". My apologies, it was a poor choice of words.
Let's put my money where my mouth is:
This is how our 20th level fighter pregen might look at level 20.
Let's say he didn't bother with feats ( or he's playing basics ) and he's trying to minimize his weaknesses.
So, now his ability scores and saves look like this:
Str 20 (+5, +11 total)
Dex 15 (+2 total)
Con 18 (+4, +10 total)
Int 14 (+2 total)
Wis 16 (+3 total)
Cha 14 (+2 total).
Against an equal level wizard (int 20), he needs to roll a 17+ to save. So, he fails his "bad" saves 85% of the time.
Bless adds 2.5 points to his saving throws; assuming he's pemanently under the effects of a bless spell, he now fails them 72.5% of the time, on average.
Assuming inspiration, he fails around 52.5% of the time (unless I've done something wrong ).
Seems good enough, right?
Couple of problems with that, though: first, we've taken a high level fighter as our example, and, as such, he got more ability score advancements than anyone else; second, he's taken a grand total of zero feats in order to minimize his weaknesses. While this is a legitimate choice, he's losing quite a bit in the customization department just to turn an auto-fail into a coin toss ( assuming the cleric is backing him up AND he has inspiration ).
Third, if he's ever granted disadvantage, inspiration will at most cancel it out, and thus our (sorta )optimized fighter is back to failing his bad saves 72.5% of the time.
Now, how much you like these specific values is a matter of taste; personally, I have an issue with the fact that I might spend a ton of finite resources, give up pretty much any customization that feats might offer in the process, get help from another party member, and still risk sitting out of the fight half the time when someone targets the wrong half of my saving throws.
Obviously, if that fits your playstyle that's fine, but it doesn't really fit mine.