This is such a weird question.
How does this billionaire exist in this hypothetical communist society? And how do you expect them to buy up a business?
It's these weird pointless thought exercises people keep throwing at me that drive me to make these posts.
If you really want to know what my desired society looks like, it's this solarpunk game my friends and I play: Fully Automated! Solarpunk RPG World Guide
Go read that, find all the stuff you don't like in it, then write Substack article about it and don't send me a link.