"What's more, the billionaires are clearly offering a clearly profitable deal for everyone, specifically so that nobody has an excuse to refuse "
When I like my land and I don't want to sell, than this is simply my right, no matter how much you think I have no excuse.
Building important infrastructure or mining critical ressources are rare exceptions for forced landsell, but not because someone wants to build a city for the rich on my land.
So sure, it is a tricky problem to buy from many owners, but getting the government to help you with your private project to force a contract on other people is kind of the definition of corruption.