Off-the-shelf enterprise gear has a chance to get a second life through remarketing channels, but much of it also gets shredded due to dumb corporate policies. There are stories of some companies refusing to offload a massive decom onto the second hand market as it would actually cause a crash. :)
It's a very efficient system, you see.
Super environmentally friendly.
The idle wattage per module has shrunk from 2.5-3W down to 1-1.2 between DDR3 & DDR5. Assuming a 1.3W difference (so 10.4W for 8760 hours), a DDR3 machine with 8 sticks would increase your yearly power consumption by almost 1% (assuming avg 10,500kWh/yr household)
That's only a couple dollars in most cases but the gap is only larger in every other instance. When I upgraded from Zen 2 to Zen 3 it was able to complete the same workload just as fast with half as many cores while pulling over 100W less. Sustained 100% utilization barely even heats a room effectively anymore!