What about a completely pointless "support the project" license? So you basically chip in for the maintenance, but don't get any additional rights?
1. Do open source maintainers actually want to commit to that?
2. What if the response is "Yes, we don't support that and don't plan to?" and the company feels this doesn't qualify as enough support and causes a headache.
3. If the purchaser knows what they're getting into, what's to say their successor also does?