[samtheprogram]

Yes it does. You can make a private, proprietary app that’s just tweaking a few bits of a BSD project. You can’t do that with the GPL.

Following that, unless the project has a CLA (so that the owner of the project reserves all rights of the code that’s contributed and essentially owns the contribution), any contributions made under the GPL cannot be made closed source, can’t be switched to an incompatible license, etc, because the contribution itself is GPL’d.

[liveoneggs]

Creating a commercial version of a thing is not a license change.

[samtheprogram]

Of course, I said proprietary. You said commercial.

Proprietary refers to ownership and licensing. While I somewhat conflated it with closed-source in my comment, it nevertheless applies since we are talking about the ability to make it closed source.

You can relicense derivative works of MIT or BSD software provided that you satisfy the original license requirements (attribution). This is irrelevant of commercializing it.

Conversely, and to your point, you can sell GPL software you didn’t write, or sell a derivative work of it, but because of the copyleft nature, your derivative work must also be licensed under a compatible GPL license.