A lot of people have already quit before the strike even started because of the boring the game is.
Legions of players also quit during ARR because of how dull the base gameplay is.
You are looking at a tiny, tiny minority on the forums who both (1) dislike the game, but (2) still tolerate/enjoy it enough to stay. Most of the "dissatisfied" population have long since quit.
I play multiple other MMOs, and I genuinely have not heard anything good about FF14's gameplay when talking to former FF14 players.
The FF14 community is a bubble. I don't think most of you realize just how boring this game is to people outside the bubble.
There's also the issue that game companies are not adept at statistical inference. They think X game got popular because of easily observed factors Y. I hate to use this overused idea, but this is unironically a serious case of correlation, and not causation. Game companies are physically unable to get causal data from their metrics, because there are too many variables that happen all at once in a game. No MMO is doing A/B testing, or running pilot experiments, or exploiting some natural exogenous variation to determine exactly what factor(s) caused a game's success.
Which is why FF14 developers don't necessarily understand that the dumbing down and simplification of the game may not be why the game was successful during COVID at all.
Lest you assume that I'm underestimating their proficiency at digesting statistics, please remember that multiple top tech firms in the Silicon Valley, who hire legions of stat, ML, econ PhDs every year, many of whom are adept at causal inference techniques, all attributed the cause of the consumption boost during the pandemic to initiatives that they've started, coincidentally, during that period, which is why they just laid off all those people after the pandemic. All of them mistake their increased financial performance as being caused by factors that were not even in their control.
They unironically need player feedback, because it's impossible to tell what caused what by just looking at the metrics.
As for why I think FF14 has been successful in EW launch? I don't think it's because this game is any good. Maybe it's better than the rest of the junk in the genre, but I believe, by far, the biggest reason is (1) the pandemic and (2) the marketing and PR.
Unfortunately, many in the community, probably including many in management at Square Enix, attribute their success to the oversimplification of jobs or the casualization of the entire game.
Which makes no sense because no player is buying FF14 because Black Mage got their non-standard lines ripped out. If you look at the player population from HW to SB, and from SB to ShB, they were also increasing a lot, percentage-wise, despite the Gordias "fiasco", despite crafting and gathering being very hard to penetrate, despite TK monk being a thing, despite dungeons actually requiring a healer to clear, despite alliance raids ending in wipes pretty regularly.