At some point he's going to run out of members to ban and all that will be left are a few sycophants, pathetic people desperately clinging to the only place they've ever been accepted, and relatively new accounts who still don't really know what's going on. His revenue will dry up, and his only option will be to open the flood gates and let people register new accounts with regular emails. Once that happens, it'll be over.
If he had any brains, he should've pretended to be one of the forum members and offered to start the new site under an alias. Tricked a bunch of the morons into basically rebuilding his little shitstain domain under a new guise.