> A Framework lets me keep the same screen which is cool

Probably the last thing I'd want to keep. Screen technology still moves forward at a decent pace. Screens are disposable, backlights fade over time, pixels get stuck, screen burn-in.

The only universal thing I can think of about machines I've upgraded over the years (not laptops, of course) are cases, power supplies, CPU coolers, and as long as the form factor hasn't changed/there hasn't been significant progress, HDD.

Everything else goes with the system. New CPU meant new socket, which also meant new RAM. Need to get rid of that old video card, of course.