the FSF/GNU can alter the GPL at their whim.
Which is, first, a false premise (they do have bylaws and promises and goals and they can't just *change* the licenses in a new version, they have to *justifiably* change them), and second, and more important, a moot premise (people can continue to develop GPLv2, LGPLv2, LGPLv3 software without any outside change to their licensing, for that you can only drop the "vX or later" on your license).
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