Capture One might cost more, but it's a one off payment. I'm still happily using CO11 (8 or 9 years old?) and if it was good enough for professional use when it came out, it's more than enough for me now.
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.