If it's completely dissolved?
In Japan? The power vacuum gets filled by Hololive's expanding influence and the other major players in the country like VSPO.
In the West? Very little changes, their relevance in the region has already dwindled significantly over time. HoloEN doesn't necessarily gain a lot of ground as the void left behind is mainly people that were largely contrarians and would never watch HoloEN. The contrarians would likely go watch something else like Idol and those that weren't total contrarians might watch Vshojo. If anything, StarsEN and First Stage would be the ones to see the biggest growth. Phase's growth would be minimal at best as a direct result of the fallout, as their only real benefit is being one of the few remaining agencies in the West with an ability to throw money around.
If it gets sold, it probably gets bought Brave. I can't speak on how that would change things in Japan but in the West, the changes would be even more minimal than if it were dissolved as many of the members in that branch are radioactive, so they're going down with the ship.