Also omitted - the amount of speculative buying for planned capacity that never actually happens. I worked for one of the big tech companies for several years, and more specialized hardware especially (ML accelerators) were spun up with the notion of "we don't know who will need these, but we don't want to not have them if they're needed". Cue massive amounts of expensive hardware sitting plugged in and idle for months as dev teams scramble to adopt their stuff to new hardware that has just enough difference in behavior and requirements as to make it hard to migrate over.

Also also, there's a bunch of "when in doubt, throw it out" - automated systems detecting hardware failure that automatically decommission it after a couple strikes. False positive signals were common, so a lot gets thrown out despite being perfectly fine.