I think it's the culmination of things.
For decades, they were cut out of the SEC because frankly they didn't bring anything to the deal. To be fair, no one did. UF sponsored them about a dozen times and most of the time, it never got to a second to bring to discussion.
They joined the ACC over the SEC because they wanted an easier route to a football championship and to advance their basketball program and also because they wanted to be part of the upper crust of academics.
They saw it as a route to jump Florida in all three while also thumbing their nose at the SEC and decades of being ignored.
Football wise, it worked great through most of Bowden's tenure. They love to point at the ridiculously long string of top 5 finishes thanks in large part to a weak schedule. It was a calculated decision and it paid off. Next year, it will too once the playoff expands. This year, it didn't.
Basketball wise, they had to watch UF win 2 titles and go to an additional two Final Fours when they were supposed to be the basketball program in the state because of the ACC (see 2020 banner).
Recently, FSU's academics finally started to improve, but they are still well behind UF.
Athletically, they have also improved a lot too but still behind UF.
And now they are dealing with an unforeseen monetary gap because they are not in the Big 2 while also dealing with fan dissatisfaction because most FSU fans still are not interested in most of their conference opponents unless they are winning big. Going to Tally is a pain for most of the fans in the core population of the state and it's not a cheap weekend.
Those little things add up if you aren't playing enticing games either because of your opponents or because you aren't winning. They are currently looking to reduce capacity of Doak to 65k as part of their current renovations. That's not uncommon now but it's a big drop.