I'm not a lawyer, but my understanding of the GPL is that the purpose isn't to retain ownership, it's to use ownership (granted under copyright laws) to ensure that the ideas can continue to spread.

The GPL doesn't prevent forks, it doesn't even prevent someone else profiting off the fork, it just requires that the fork can also be shared freely.

Exactly why I used the MIT license, even if it is on my ultimately non important stuff. I'd rather it was out there (potentially) being used by anyone that wants to for whatever purpose.