Maybe I am wrong on this but would the best choice for someone like Ironmouse and the other more well off VTubers not be to now start their own agency where they can literally advertise it is owned by the talent themselves? All they need is a handful of people (marketer, merch distributor, lawyer) which it sounds like most have or are things they can outsource to third parties, everyone just agrees a cut of all their individual income gets put in a shared pool they can all view. Any new talent who are already established could choose to "buy in" to get a set amount of revenue share and if they wanted to get brand new talent off the ground, they could use the company funds to invest into new VTubers, taking an extra cut of their revenue until they are out of the red.