The whole Big Tent inclusiveness thing was trumpeted from the beginning of the playtest, "innocuous enough to avoid edition warring" is just my cynical spin on it.
It has, the same sort of feat Marvel did, just for a lot less money: it took a 40yo property with a nerdy, even cultish, positively disgruntled fan base, and rebooted it in a way that didn't outrage their peculiar expectations and prejudices, while still being approachable enough to sustain a resurgence in interest from more mainstream customers.
The former required returning to a more traditional feel, including restoring perennial, intractable, structural issues like LFQW & 5MWD, that had only recently been solved, and falling back on the best traditional way of coping with them: the DM.
The latter required toning down the steep learning curve of TSR era baroque heterogenous sub-systems ( which even 3e had managed) and the high bar for system mastery of 3e.
The resulting compromise isn't as evocative of the True D&D Experience as the OSR, nor as approachable and quick/easy for new-to-the-hobby potential players to learn as 4e, but it avoided the kind if controversy from established fans that would keep potential new ones from even trying it, and it was readily accessible to returning fans, while not being too off-putting to new ones.
Looks? At a glance it looks like 3e or 2e or 1e: there are spells/day tables.
But you don't even need to pop the hood to see that those tables are a lot more similar to eachother than in 1e, for instance - and, there are /at-wiil attack cantrips/, unthinkable under The True Way of Vance.
While not accomplishing the same things, and being limited to primary casters, unified progression, viable at-wills for all, and two recovery cycles are clearly retained from 4e.
5e /is/ very much a return to the feel (and failings) of the classic game, but not by re-winding to 3e and fixing it up, but by intentionally breaking 4e.
Are in no way surprising if you were aware of the BA goal. Bonus stacking, thus buff stacking and the systematic (and wasteful) 3e-optimal strategy of pre-casting, were simply off the table, they couldn't be added back the way 9 spell levels and LFQW could be.
If there had never been an intervening edition that /actually/ fixed those issues, the net, non-trivial reduction in their severity could be rhetorically exaggerated as a 'fix,' but, misrepresenting the re-introduction of solved problem as a fix by disingenuously ignoring that they had already been solved is counter productive in any discussion, even this one.
5e gamers - The new/returning ones driving the not-seen-since-the-80s-fad sales of D&D have zero appetite for learning a second RPG.
PF1 leveraged the improbable confluence of the edition war, the OGL, and a database of Dragon/Dungeon subscribers, to, essentially, take up the mantle of D&D with existing 3.x D&Ders.
That opportunity has run its course.