> hardware running 100% won't last five years

Five year is a pretty typical amortisation schedule for HPC hardware. During my sysadmin days, of CPU, memory, cooling, power, storage, and networking, the only things that broke were hard disks and a few cooling fans. Disks were replaced by just grabbing a space and slotting it in, and fans were replaced by, well, swapping them out.

Modern CPUs and memory last a very long time. I think I remember seeing Ivy Bridge CPUs running in Hetzner servers in a video they put out, and they're still fine.