I have to agree here a bit. However, there was nothing stoping Rethink from building their own service and promoting it as the "official" RethinkDB service. They have the unique opportunity of making it better than any other service by:
-Updating the service the day new versions go GA
-Faster turn around on breaking changes
-Ability to provide authentic expert support
-Ability to provide additional functionality power users would pay for and 3rd parties like compose would not implement
They wouldn't capture the entire market but they could be the leader in it.
The open source business model is hard enough. It becomes very difficult when every other Cloud simply wants to offer your product and you capture none of that. And then the project dies and no one wins.
Open source companies need to be the leaders of their tools, provide the best services around them and differentiate their offering from the open source code base. If you can't do that you won't have a company. Asking for donations is not a business model.
RethinkDB was a good database with a bad business.