Sure, but 3.x still had lots of rules for the "other stuff." Whether that is a good thing or not is a point of preference, but those rules were there
It's not just about rules, though, but about their quality.
The AD&D Wilderness Survival Guide has lots of
rules for travel, foraging, weather, tents, etc. But many of them are terrible, in multiple ways: almost impossible to make practical use of; not particularly verisimilitudinous in the outcomes they generate; not well-integrated with other parts of the game (eg why does Heatstroke cause loss of CON, but all other sorts of damaging and exhausting effects in the game don't); etc.
There are other ways that things can fail to integrate well, too. For instance, in D&D DEX covers reaction times, agility, aim, etc; CON covers muscular endurance, cardiovascular fitness, general rude good health, etc; STR applies to climbing and running and jumping and punching; etc. This is all very general. So why would we get weirdly granular when it comes to (say) enduring the rigours of melee combat as opposed to the rigours of climbing a mountain? It makes more sense, in the context of the game, to be general here too.
Magic spells of food and water creation are perhaps at the more boring end of trying to integrate
survival into the level-based power-gains that are part of D&D. But to me it seems very clear that having high-level PCs worry about survival when trekking across a mundane desert isn't a viable, integrated alternative.
