KanYe is a billionaire (on paper) through equity and stock options via Yeezy INC.
That money is not liquid, he'd have to sell off shares which is something you don't do.
It wouldn't be a financially literate decision to sell off company stock options to purchase right to his masters. It'd be hustling backwards, which is why he's probably trying to do this PR rollout to essentially have public opinion put pressure on the opposition during negotiations. Can't really gauge how effective it will actually be though.