Of course they don't owe them anything. Ubuntu's reputation is built primarily on people who use it (or used to) for free. They are/were Ubuntu's advocates and what made it popular.

So just as they made it popular, they can make it unpopular. People like me will simply post on our blogs and social media that they should not install Ubuntu. A typical Ubuntu user is not that high on the tech scale, and they listen to people like me for suggestions on which distro.

Cut the pipeline that feeds into it.