Not long ago, after tiring of his whining about not being able to play D&D, I got my old 2e DM to join my current play group. Of course, he pitched his 2e campaign to see if anyone wanted to play (he's been adding to it for 35 years now...I think, I only started playing in his campaign in 1991).I did read your full post, but I think this quote sums it up. We just started playing 2E again last Sunday after 22 years and my friend and I who used to play together back then thought, eh we'll wing it at first, it'll come back to us, it did somewhat but it was rough at points. The other player who has only played 5E is somewhat confused. I just started reading the PHB over the last few days and I'm astounded how much I forgot, how many rules we probably never used to begin with, how much we probably had wrong, and how different the game truly is from 3E forward. It really is a different game.
So we tried playing 2e. And wow, was that a mess. Arbitrary rules, huge variance in player ability, classes that can barely function at low levels, trying to explain "ok, roll high to attack, roll high to save, roll low to make ability checks, roll d20 most of the time, but here are some d% rolls", trying to field questions of why AC goes down, or why sometimes a bonus to AC is a positive integer and sometimes it's a negative integer, or why there's a huge list of Non-Weapon Proficiencies but most characters get 3 of them (not counting some that cost more than one slot!), Kits, what Charisma even does, weapon speeds, how slowly characters advance (the guy who thought his Elf Fighter/Thief/Magic-User was the bee's knees balked when I explained how leveling up would work for him), and then an argument with me and my friend about using "languages known" to get more proficiency slots (he was fine with them being used for NWP's, but the language doesn't differentiate, since the Fighter wanted to know how to use more than 3 weapons without penalty- I tried to pitch the Blades broad group from the Fighter's Handbook, but 1, he wanted a bow and a melee weapon, and 2, the DM doesn't like weapon groups)...I could tell none of the newer players were having any fun.
And if that wasn't enough, the DM also tried to infuse some 1e rules on top of this "Jimmy, you know I use Comeliness in my games". "Oh yes, because they're not already confused, do you want to use weapon vs. armor types while we're at it?".
We had two sessions of this, but I wouldn't be shocked if we only played one, and the rest of the time was character creation and explaining rules.
I loved my time playing AD&D, many fond memories (and some not so fond memories), but despite any nostalgia, I definitely remember now why I was so quick to switch to 3e when it came out.