As I've already mentioned a few times, you can still license stuff software with a 100% codebase by licensing your trademarks and artwork. You can also sell support for your software, get money for new features, for certifications, hardware support, etc. Your code is still fully open, people can send you patches and you are not alienating your community. There are companies using this formula rather successfully.

Not saying that Jolla is willing and prepared to do it like this, just that it is possible to license & earn money with what is effectively 100% open source software.