OP: Yes and no? I'd wager the rest mechanic is largely a product of the type of game, table preference, and in some cases the type of table in general. My kid's game is whatever they want (usually when they get bored). My hexcrawl will be short rest/day, long rest/week. The 'generic' tables I've been on - FLGS and Roll20 - generally follow whatever the rest recommendation in the module is. Roll20, as a 'table', is easiest to stay on 6-8 target as it's kinder on session breaks so you don't have to take a long rest at the end of each. You can just stop mid-fight, even mid-round, and it's all there for you next time without much fuss (you can even click buttons for PCs who are late/missing).
Our long term home game DM goes by the adventuring day XP table in the DMG, not the 24 hour clock for long rests. She doesn't like the "a short rest is a lunch break and a long rest is going to bed" concept - she adjudicates them as an actual activity. A long rest is 8 hours, at any time of day, spent studying spells, sharpening weapons, mending armor, eating, and so on - all things that are tough to do while you're asleep. Short rests are subject to narrative availability, but overall she tries to match it to 1/3 and 2/3 ADXP when building adventures. Rests generally correspond to her adventures (e.g., this ancient crypt has an adventuring day's XP worth of challenges in it) or her narrative breaks. Resting outside them usually results in a narrative setback since the world doesn't stop turning while we rest.
We're 16th level. That's 20k XP each (so, no, it doesn't need to be, or is it, all combat earned) before a long rest. Once we get around 7k, which can be a day or an hour, based on the encounters, she narrates a short rest opportunity. Sometimes we take it, sometimes we don't, and sometimes we can't. Same at 14k. Once we get to 20k, we've either cleared the dungeon or finished apprehending the Baron's assassin or what not and we take a long rest. If we don't reach our objective, she narrates dull blades and exhaustion - letting us know in-game not on-sheet we are running on empty. Sometimes we pop a tiny hut and suffer the narrative setback and sometimes we push on depending on how things are going.
Edited to dispel the wall of text