I also think PF1 was a lightning strike. It was the right product at the right time when D&D was bein mishandled. Now, it's just another D20 game
Well, "lightning strike" makes it out to be sheer luck with no planning.
I think there was plenty of time since the release of 5E to figure out a game with as many similarities as possible that still allow the greater crunch depth people feel are lacking from 5E.
It would have reproduced the main benefit of PF1 - being more of what D&D gamers wanted.
The only difference is that WotC isn't abandoning 5E the way they abandoned 3E, but this difference is smaller than you think: no, 5E isn't abandoned, but isnt meaningfully expanded either.
So let's not view the success of PF1 as something that can't be analysed, because it can be analysed.
What Paizo must accept is that they siceed only within WotCs orbit.
Without D&D they are, as you say, just another dndish game publisher. There are literally hundreds of such games forgotten and disused.
The only way, I believe, Paizo can stay as big as they became, is by keep playing in WotCs backyard; by releasing a "5E advanced" as it were, fulfilling a huge demand that WotC for some reason seem utterly disinterested in.
But they went with a game where you each level are asked to choose between hundreds of feats, very few of which make a meaningful difference. A game that feels like 4E in several regards.
Did Paizo design PF2 in an utter bubble with zero contact with the real ttrpg hobby for the last ten years or so? PF2 feels unapologetically and apocalyptically out of touch with the times.