There are forks though. The only version i don't think that has a fork is GNOME 1 but... the code is out there (and there is an actively maintained GTK1-based toolkit that was posted here not too long ago, though you may need to make some modifications to the GNOME 1 code to work with it as IIRC it isn't backwards compatible).

People made CDE to work on modern systems and IIRC CDE wasn't even compatible with Linux when the code was first released.

You can always fork it if you don’t like the choices they make

That’s the point the OP is trying to make about the advantage of open source

That's happened like three times to the extent that the forks are more widely installed than the original

And people did but it is hard against Redhat that has actively made harder and harder to use Gtk+ outside GNOME.

What changes have been implemented in GTK that make it harder to use outside of a GNOME environment?

practically everything in GTK 4. It removed menu bars ffs

But you can also use MATE still to this day, or even Cinnamon.

Hey! Someone sneaked into my brain and wrote down my exact comment!