You know....I am starting to think all those OSR players need to quit playing overpowered characters and come play a gritty 5e game where killing a troll takes half again more fireballs, magic missile really isn't much more than a nuisance past 5th level, spells don't autoscale, there are few spells with duration you can have running simultaneously , and nobody, I mean nobody, ever gets two wish spells a day. Or even 4 fireballs.
Sure, 5e spells come back faster and its more likely they can be cast in combat...for all the good that does us. You could never drop an uninjured troll to its knees with a 5e magic missile using a 1st level slot. Targets make a save every round. EVERY. ROUND.
What's that? Five fireballs? At 13th level? And they do 13d6? That's playing "God mode", my friend. Might as well turn on "no clip" and walk through walls. Magic users...spoiled brats the lot of 'em.
Given that you have a strong desire not to look at rules in a vacuum, this is a passingly strange comment to make, no matter how jokingly.
Let's look at this!
First, Magic Users in 1e reached "name level" at 11. Again, 11th level. So you're right, in way. 13th level is practically god mode. To even cast a ninth level spell you had to be 18th level, which is practically unheard of in an AD&D campaign.
But let's think about the name-level wizard in AD&D, shall we?
First, they have no combat cantrips. None. Instead, at 11th level, they have proficiency in two weapons. That's okay, because you can only ever get three. Staff, dagger, dart. Pick two. That's your go-to. Not a scaling damage cantrip. But you don't want to be in combat, because you have approximately 23 hit points. Okay, let's assume you got max hit points at first level. You have 27 hit points. And a bad AC, because you can't wear armor. Which means that you can probably get taken out before getting a spell off. But even if you aren't, if you're hit, you still don't get the spell of. And unless you're casting one of a very limited number of spells (Magic Missile, Power Word), you're going to go last in a round.
Next, your spells are 4/4/4/3/3. But are you actually using them all in a day? That could be a problem. Not only do you have to memorize them (and select them ahead of time, VANCIAN FTW!), but you need to get your eight hours of sleep in, and then spend (1+2+3+3+3.75)= 12.75 hours memorizing your spells again! So there goes another day. Sure hope you weren't doing anything important.
Oh, you memorized only fireballs? Gee, that's a shame, given that you are indoors, or in a city, or in a dungeon, or in any inconvenient location that doesn't take into account the size of the explosion. Maybe you wanted a lightning bolt? Of course, if all you took were those spells, you missed out on some of the pretty useful other spells you get there. I mean, I can imagine parties that need Leomund's Tiny Hut sometimes. Or Dispel Magic. Or Fly. There's a lot of useful spells there .... shame you wasted them all on fireball. Maybe you need to take another day off and re-select some spells since you aren't just troll hunting for DPR.
Oh, and the monster you encountered has magic resistance? Shame.
I don't want to oversell this. A name-level MU in 1e was pretty awesome. Just like any name-level character. But they weren't god mode. And it was rough sledding for a long time playing a MU as well. To try and compare casters in any edition in the WoTC era to the TSR era is a laughable exercise. Because magic has become ubiquitous. That's neither good nor bad, but it certainly is.