Because ... it’ll just work : Nope
Because it works for a damn long time.
I have almost every generation of Mac Mini filling up one cupboard and get one or other of them out occasionally to power up and play with. That’s just an example. On my experience you get at least three times the usage from an Apple machine/device, which will be years out of date before it breaks down. It’s almost frustrating that with all the latest backup systems available my ancient Time Capsule still bloody works!