Having played AD&D, I agree with most of this, but didn't all those spells exist too? Clerics could create water (and later food and water), Leomund's Tiny Hut was there (though, admittedly, it wasn't an invincible bivouac), etc.?
This is something that always surprised me when I started playing 3e. Suddenly, a spellcaster's ability to trivialize wilderness survival was a big deal among a lot of DM's I played with, and quite a few on early forums, and has remained so to this very day- but the precursors of all these spells were around in 1st and 2nd Edition! Did no one use them back in the day?
As mentioned, the spells were different. It also took a long time for you to get your spells back, especially at higher levels. There was also a lot more explicit control over what spells were in the game in AD&D than now. So if a DM didn't want Leomund's Tiny Hut in the game, the magic-user simply never got it. That was written into the rules of how magic worked.
Regaining spells was an ordeal in AD&D. Minutes or hours spent in study, prayer, and/or meditation. Every single day. Not just automatically pop, you get them after a nap. You had to rest a certain amount of time depending on the level of spells you wanted to recover, from 4 hours for 1st-level spells up to 12 hours for 9th-level spells. After that rest was completed in full...and this was the days of wandering monsters and any combat interrupting rests...you had to study, pray, and/or meditate for 15 minutes per spell level...for each spell...memorized individually. So if you memorized fireball once, you got to cast it once. You memorize cure light wounds twice, you got to cast it twice. So those "nice lazy days of just healing the party" were incredibly risky. You don't pack some combat spells and you get hit with a wandering monster...you're screwed. Most times you'd go into a delve as rested and prepared as you possibly could (and armed with as much information as you could and as many dirty tricks and combat as war shenanigans up your sleeves as you could manage) and know that it was time to head back when you were about 60-75% down on resources otherwise you'd be overextended and not likely to make it back home alive. There was no setting up Leomund's Tiny Hut in the dungeon and just getting a rest.
Also, the text of the spells are wildly different, take Leomund's Tiny Hut as an example. It should also be noted that in AD&D Leomund's Tiny Hut cost you a third-level spell slot whereas in 5E LTH is a ritual...so you can cast it an infinite number of times. Text from each edition below.
AD&D:
"When this spell is cast, the magic-user causes an opaque sphere of force to come into being around his or her person, half of the sphere projecting above the ground or floor surface, the lower hemisphere passing through the surface. This field causes the interior of the sphere to maintain at 70° F. temperature in cold to 0° F., and heat up to 105° F. Cold below 0° lowers inside temperature on a 1° for 1° basis, heat above 105° raises the inside temperature likewise. The tiny hut will
withstand winds up to 50 m.p.h. without being harmed, but wind force greater than that will destroy it. The interior of the tiny hut is a hemisphere, and the spell caster can illuminate it dimly upon command, or extinguish the light as desired. Note that although the force field is opaque from positions outside, it is transparent from within.
In no way will Leomund’s tiny hut provide protection from missiles, weapons, spells, and the like.
Up to 6 other mansized creatures can fit into the field with its creator, and these others can freely pass in and out of the tiny hut without harming it, but if the spell caster removes himself from it, the spell will dissipate.
The material component for this spell is a small crystal bead which will shatter when spell duration expires or the hut is otherwise dispelled."
5E:
"A 10-foot-radius immobile dome of force springs into existence around and above you and remains stationary for the duration. The spell ends if you leave its area.
Nine creatures of Medium size or smaller can fit inside the dome with you. The spell fails if its area includes a larger creature or more than nine creatures. Creatures and objects within the dome when you cast this spell can move through it freely.
All other creatures and objects are barred from passing through it.
Spells and other magical effects can't extend through the dome or be cast through it. The atmosphere inside the space is comfortable and dry, regardless of the weather outside.
Until the spell ends, you can command the interior to become dimly lit or dark. The dome is opaque from the outside, of any color you choose, but it is transparent from the inside."
So those bolded bits are important. It goes from a minor effect that costs you a 3rd-level spell slot...to a globe of invulnerability to everything, including magic (except dispel magic), that you can cast an infinite number of times.