RIP Smash at EVO. My guess is that if anything it probably has to do with the sponsorship with Panda Global + New Management moving in. A shame Smash won't be at EVO, but honestly, given a lot of things, I think they both no longer need each other. Besides, both the competitive smash scene and Evo have their fair share of toxicity involved, so I think the conditions in both need to improve drastically first. (Hopefully, the new management can fix the problems on EVO's side at least, I have confidence they will, not so sure about the smash community.
And I also don't think this will affect the dynamics of EVO. To assume a game needs to be in or deserves the EVO slot is kinda ugh and shows how the FGC is so western-centric (which reflects on it's toxicity)
Isn't Smash still at Combo Breaker?
Ultimate still runs at Combo Breaker, but no Melee, and even then it's deemphasized. Nintendo doesn't show up as a sponsor of the event. I think Nintendo isn't going to simply restrict Smash from every major tournament event simply cause it isn't part of the official circuit. Remember Nintendo once attempted to shut down Smash at EVO, so I'm guessing they had to get more special permissions for Smash.