For sure, a one off protest by a couple of thousand fans isn't going to make him leave. But next season fans will be back in stadiums (hopefully) and you could have literally tens of thousands making it very clear they want their owners to leave. Not just chants, but repeated mass walkouts during games. If they carried that on for several weeks I think that might well be enough to make owners quit.
Trouble is, in this economic climate, who's going to buy a football club for a couple of billion?