> Which I was going to mention is contradictory, because the point of permissive licenses is that it does not have to be Free forever.

No, the point of permissive licenses is that third-party derivatives, which have no impact on the licensing of the original, don't have to be free ever, while the point of copyleft licenses is that they do.

Neither has any effect whatsoever on what future first-party licensing can be; a commitment to "open source forever" by the copyright owner is mostly orthogonal to what kind of open source license the copyright owner offers. (Now, its true that if the owner accepted contributions under a copyright license rather than under a CLA, they would likely have no practical choice but copyleft now and forever, but that's an issue of the license they accept on what they can offer, not an effect of what they offer itself.)

(OTOH, using "permissive" for GPLv3, a copyleft license, is actually contradictory, as you correctly note.)

The license of the code released under a permissive license is guaranteed to stay the same.

Only the code that is yet to be released is not.

From an end user perspective BSD/MIT and GPLvX licences offer the same guarantees. It only is different if you are a contributor or if you intend to distribute modified or unmodified code yourself.