[mlinksva]

If freezing legal status of a project forever is short-sighted, the ability to opt-out of upward compatibility in GPLv2 is a tragedy, as is the same in GPLv3. If there ever is a GPLv4, hopefully it will be purely GPLv4+ with no option for GPLv4-only.

[cube13]

You're assuming that you're going to agree with the terms of GPL5. That's certainly not a good assumption(See Torvalds, Linus).