I agree with that goal, though I'm hard pressed to think of examples where it really has gotten to that point. The rote example is the cleric as the healer, but I don't think it's essential, nor is it all that exclusive (though the earlier you go, the more so it was).
I'd say it reached that level in 2E AD&D, myself. In D&D, there was rarely an assumption of a player Cleric/healing/curing in adventure design or monster design, so it wasn't a huge issue. In 1E it started to become more assumed, and by 2E, a huge proportion of published adventures (and a lot of DMs) assumed that there had to be a Cleric/Priest/Druid in the party, and were extremely hard to run as written if not (requiring rejigging encounters, changing basic assumptions, and so on, imo of course - you could always just let the PCs fail, after all!). You started to see advice about how you could convince a player to be the Cleric, and I know I was aware of "nobody wants to be the Cleric!" as a trope long before the internet existed (ironically, I often wanted to be the Cleric - but I was a DM most of the time). There were Cleric-alternatives, but they were all either basically the same thing (Speciality Priests, fr'ex) or kind of horrible (Mystics), and they were virtually all god-botherers of various descriptions. That was kind of the big problem - unless you had a hundred weird sourcebooks, if the party wanted healing, you needed a god-botherer (or spirit botherer, maybe), and most players I knew (and indeed this continues to be true now and in MMORPGs and so on) had very little interest in being that - their dreams were of mighty warriors, powerful wizards, sneaky thieves, and silver-tongued bards, but not of, like faith healers in plate.
2E obviously
could and was be played without a player or GMPC Cleric (resorted to the latter a few times), but it was a drastically different game, where the PCs had to frequently retreat for weeks or pay a lot of cash to churches (or the GM supplies vast quantities of healing potions, I suppose), and there's nothing wrong with that game, but it's a different game. Whereas missing a Thief or a Fighter or the like pretty much never had a similar effect that I saw (Wizard is debatable - but I literally never saw a party without at least a multiclass Wizard, so I can't speak from experience there).
3E weakened the niche protection a bit on healing, but assumed healing in an even more hardcore way, so you had this curious situation where people couldn't heal much without magic, and were expected to be on full HP all the time (by CL/EL stuff), but that magic could be a cheapo wand of CLW.
4E got the best balance here, imo - a Leader character is a tremendous asset to the group, but fairly rapid natural healing, the ability to use Second Wind and so on, means that the game only changes a little without them, and you don't typically need to re-write adventures, or re-jig encounters or the like. Plus you can have any flavour of Leader - not just different kinds of god-botherer.
I suspect that there are fair number of adventures out there that are completely different or non-viable without a Wizard or similar arcane spellcaster, too, in 2E/3E. Especially at mid-high levels. I know I've read adventures that assumed AOE spells would be used to deal with certain encounters, and had few solutions if not, or assumed ready access to fire damage and/or electricity damage.
Talking of Rogues/Thieves, one very curious element of niche protection is that D&D, up to 3.XE/PF, at least, has fairly zealously protected instant-death and save-or-suck-type stuff as the domain primarily of Wizard-types (occasionally Cleric-types), even though, in fantasy fiction, Rogue-types often instantly kill people (even serious people), and routinely horribly poison them and so on. It seems like it was seen as wildly overpowered if a Rogue could one-shot someone from full health (even if only when the stars aligned, or limited to once a day or the like), but fine if a Wizard could do it to multiple people per combat.
Similarly with killing a bunch of people in a single round (even when rounds were 1 minute!). Okay for a Wizard, not okay for a Fighter (unless they're 1HD or less, or not much more than that).