You can exclude companies that have multi billion company in their tree.

So someone launches a new company that provides services for everyone, including billion dollar companies.

Basically unless you put a non-commercial license on it, any effort to limit its use will be easily circumvented.

You cannot circumvent that. If you want to do a service for a company that has a multi billion company in the chain then you would have to get full commercial license and when that happens you simply raise an invoice to the client that covers this cost. It is pretty simple and you cannot get around it.

The middle man increases costs and inefficiency for the billion dollar companies, giving a competitive advantage to everyone else. It's foolproof I tell ya!