The dmg lists several different styles of play and adventure creation. I would argue,
as others have done, that dungeon-crawling is more heritage at this point, and not really indicative of how people play, which is why this issues comes up so much (I would wager it's the most common gripe with the mechanics of this edition from what I've seen). Dnd has this wide open narrative framework in which anything can happen and then says, you must do 6-8 of this very particular thing, which is tied to
in-game units (short and long rests). So if short rests aren't possible in the dungeon you've created, the game "breaks." At least a game like 13th age is more honest about how it approaches resource recovery, and 4e more honest in encounter design, though neither is my cup of tea.
fwiw, this style of play (6-8 discrete medium and hard encounters with exactly 2 rests) isn't really a "dungeon crawl" in the bx/1e sense.