I think that they got out of Birminham whilst City were still a PL club and got good money for it. Selling West Ham is a whole different ball of wax.
They're subject to financial repayments on profits of sale, I think up to 10 years after becoming tenants, so an immediate sale is unlikely...particularly as they may have their beady eyes on becoming owners of the stadium at a significant undervalue.
So, they'll want to hold onto it but it's hard to see how they can do that without becoming absentee owners or creating chaos in the stadium.
They've managed to keep just ahead of the the angry locals for a decade. It's been a decent run but I can't see this ending well for anyone if it drags on for years....well, apart from us of course...