[mrighele]

That depends on how old and big is the project. For example Linux is "stuck" on GPL2 and even if they wanted to move to something else it wouldn't be feasible to get permission from all the people involved. Some contributors passed away making it even more difficult.

[LeFantome]

Not exactly “stuck” since they very explicitly do not want to move to GPL 3.

[CaptainOfCoit]

Even if they wanted to move to another license (which they don't), they wouldn't be able to do. So sounds exactly like they're "stuck", regardless of what they want.