More than anything it just isn't worth it. The prize pools and other money are just really miniscule for players, cost a ton of money, and the bigger players actually make money just sitting home and re-streaming it.
SF6 had a $70k prize pool in 2024, and you "only" had to beat out 5,254 other people for the chance to win some money. That's also the entire pool, so 8th place took home a whopping $791 dollars - so probably doesn't even cover the travel. If you have a tournament with 5,255 people and only 8 make their money back - you aren't going to have a tournament with 5,255 people for very long.
Warner Brothers took their money out of Evo, leaving MK1 with the minimum prize pool (which one of the three people who give a fuck about MK are going to win anyway) and stuffed it into their own ill-advised Pro Tour. So you don't even get people chasing the money that used to be the Netherrealms games. Looks like Capcom did the same a while back with Capcom Pro Tour and Tekken never really invested in the scene and has no money to take out.
For comparison - Clash of Clans is played in a team format (5 per team) but with a $1,000,000 prize pool, so in the same year - your average Clash of Clans esports player was making 3 times of a SF player was, which is roughly six times more than Tekken/MK/whatever else.
All of this to say - there are very few people who look at the FGC esports scene and think "Yeah I'd love to fucking grind out this dogshit Mortal Kombat game and go to evo (booking my own travel) for the chance to win $450 if I take 7th place. It'll be cool I'll get to hang out with cool guys like all of these trannies and SonicFox". No one want to watch a live stream where a once-a-year event has $20,000 on the line. Family Feud gives out $100,000 (or $80,000 and a new Sponsor Car).
Evo has the same high stakes as the discount game shows on Over-The-Air broadcast networks. It's a lesson they never learned (probably because Mister Wizard was too busy using Evo to be a kiddy fiddler) but Evo never really had a long term strategy for "what if these game companies simply run their own annual tournaments?" and you're seeing the end result.