I'll worry about that when it happens, but I'm more than happy with my D500/D850 for the foreseeable future.
That's super annoying that you often need a new version just because you got a new camera
You don't 'often' need a new version, if you bought Pro today it'd work with all current gen cameras from the major manufacturers, and probably get updates for a couple of years.
I understand that Capture One aren't going to support old software for decades, and I'm fine with that.