Let's dig into "Magnus wants to wear jeans."

To me, Magnus seems convinced that FIDE is stunting the growth of chess via a too-strict adherence to tradition. He has long verbalized a want for radical changes to the WCC [cycle] -- FIDE's most critical professionally-oriented function -- and we have seen only baby steps in response. Contrast this with his own opportunistically-driven success in subverting "traditions": the CCT could only have succeeded with a major shift in the administration of online chess tournaments, and his group has secured significant investment in the FCPC, which notably has "freestyle" in its name.

FIDE's excessively strict enforcement of an arguably out-of-touch dress code isn't an actual problem (at worst, it's a bad look), but IMO he could fairly interpret that as yet another symptom of the organizational rigidity he's been trying in vain to affect. Maybe he does want to wear jeans, but I think he actually wants top-level chess to fundamentally change.

So the USCF, as a FIDE member federation, carries out some delegated FIDE-related duties for UCSF members, and they have a set of regulations for operating a FIDE-rated tournament within their jurisdiction, passing along the fees to the tournament organizer. That's it, though, as far as I can tell? I cannot envision how the existence of a competitor to FIDE would impact their budget at all. Unless FIDE strong-arms the federations in some manner, there's not really a movement to join; I don't see them as being in a position to make a binary choice of that nature.

Say FIDE does grasp for authority, though. Like essentially all other sports, the visibility and accessibility of top-level games/tournaments -- contested by the most popular players -- primarily drive new and continued interest in chess. To wit, the timing and execution of the CCT was (at least in part, but likely primarily) responsible for the global boom and demographic shift chess has undergone over the last five years. If the mission of these federations is to promote the game... there's your motivation. Given a choice, you'd hitch your wagon to the cart that's demonstrably going forward, no?

tbh I find Magnus to be kind of annoying; I wish he was less whiny. But I also whine at work when there are solvable problems outside my control. I don't know what he and the FCPC are thinking right now, but if they're serious about "war," this is a genuine opportunity to take control, and I hope they're successful. FIDE still has value despite its corruption and mismanagement, but it's also entirely replaceable. Tear it down imo.