I'm not the one building out datacenters but I believe the power consumption is the reason for the devaluation. It's the same reasons we saw bitcoin miners throw all their ASICs in the bin every 6 months. At some point it becomes cheaper to buy new hardware than to keep running the old inefficient chips, when the power savings of new chips exceed the purchase price of the new hardware.

These AI data centers are chewing up unimaginable amounts of power, so if nvidia releases a new chip that does the same work in half the power consumption. That whole datacenter of GPUs is massively devalued.

The whole AI industry is looking like there won't be a first movers advantage, and if anything there will be a late mover advantage when you can buy the better chips and skip burning money on the old generations.