Lately there's been a lot of relicensing stories this year, mongodb[1] being the one I thought of first. It seems like the GPL is just a way for groups to protect their own assets without getting ripped off, and more permissive licenses (BSD, MIT) don't give the creator of that software the same protection. However, if you do violate the GPL and release a closed-source product, who's to tell? Who will know? Always struck me as weird.

[1] https://www.zdnet.com/article/its-mongodbs-turn-to-change-it...