Have you considered just beige boxing a server yourself? My home server is a mini-ITX board from Asus running a Core i5, 32GB of RAM and a stack of SATA HDDs all stuffed in a smaller case. Nothing fancy, just hardware picked to fulfill my needs.
Limiting yourself to bespoke systems means limiting yourself to what someone else wanted to build. The main downside to building it yourself is ensuring hardware comparability with the OS/software you want to run. If you are willing to take that on, you can tailor your server to just what you want.
Yes, but that is also going to require a ton of extra effort to track and assumes the nozzles themselves wear consistently. There would probably also need to be modifiers based on materials used, and even brands. For a professional print farm or a business trying to squeeze every last dollar out of the operation, this might be worth it. For a hobby where we expect a lot of waste? Eh, fuck it, just replace it when prints start going south.