Sf6 is popular for its own reasons, it has a great on-ramp for noobs with modern, the drive system is very intuitive and driven impact is most of what you'll have to worry about at low level, and it's got a really good culture surrounding it in Japan to get people interested and picking up the game, the west completely fails at this, mostly NA
I'm in shock that no other fighting game has been able to replicate this, they keep tripping over their own shoelaces in various ways, whether it's insane system complexity like 2xko, netcode/online issues with other games/lack of interest leading to a doom spiral
Tokon looks like the only game since SF6 that could actually get the golden combination of casual appeal/learning curve/interest needed to be self-sustaining and attract new players