It's only that simple if it's all written by the same person.
A maintainer can't just re-license the whole project unless all other authors agree (or already agreed to that e.g. by accepting some contributor agreement).
Or did you mean a price high enough to just ignore the existing license?
That's an interesting dilemma. If your goal is to get your source code to be used by lots of people, then it seems logical to use an as permisive license as possible to "compete" with other open source projects. But it might be short-sighted, because then if your code gets incorporated in proprietary projects it may become used a lot, but it won't propagate, it won't generate new projects that might get even more use. If on the other hand you want to get your source code into the hands of as many people as possible (that is not only users but empowered ones), that's different, and a licence like the GPL that is inherited (I don't like the term "viral" very much, it seems too pejorative) seems better, but then they can't compete against more permissive licences, so they can't "reproduce" that well either !
This is a "tragedy of the commons" of sorts. If all open source projects could collaborate and choose a single license, what would it be ?
It's not a dilemma at all for those that explicitly choose the GPL over MIT because they believe in Free Software (others might choose GPL for other reasons....).
Being Free and having every user of the software retain their Freedom is the literal point of the GPL. Saying "hey, your software would be used by lots more people if we make a proprietary product out of it" is undermining the entire point of the Free Software movement....
So it's more ethical if 10 people use your software and they retain their Freedom, then it is for 10 million to use it bundled in a proprietary product.
> If all open source projects could collaborate and choose a single license, what would it be ?
I don't think this is possible really. Even the FSF who IMO are some of the most vocal supporters of user and developer empowerment created the LGPL to solve this very problem. Some of their software (like glibc) is licensed under the more permissive LGPL instead of the GPL to foster adoption[0].
An except from [0]:
> This is why we used the Lesser GPL for the GNU C library. After all, there are plenty of other C libraries; using the GPL for ours would have driven proprietary software developers to use another—no problem for them, only for us.
