There is absolutely nothing harmful about permissive licenses. Let's say that Wine was under the MIT license, and Valve started publishing a proprietary fork. The original is still there! Nobody is harmed by some proprietary fork existing, because nothing was taken away from them.

It's harmful to the ecosystem, because the reason so many Linux drivers, and Wine contributions, and a lot of other things are free software today is because of the GPL

A decade or two ago Wine was on permissive license (MIT I think). When proprietary forks started appearing, Codewavers (which employs all the major Wine contributors) relicensed it as GPL.