I think another big part of it is a desire to return to "personal computing" in the personal sense, as a reaction against subscription everything, sandboxed app

I think another big part of it is a desire to return to "personal computing" in the personal sense, as a reaction against subscription everything, sandboxed app everything, polished everything. Cyberdecks are under your control, from the design to the keyboard, and a person is probably more likely to be running something personal like Emacs on these machines than some Electron groupware.