If you want a new CPU after a decade it's absolutely as you describe: you need a new mainboard and probably new memory (DDR5 just came out), and end up keeping only the case, drive, case fans and PSU, if that.

For other components it mostly works. You can smoothly upgrade from 8GB RAM all the way to 128GB, get a new GPU, whatever the current WiFi standard is, more silent cooling, more, bigger or faster drives, etc. If you replace something every 2-3 years you can ship-of-theseus the same computer for a surprisingly long time at pretty low cost