The fibre in the ground from the dotcom bubble was still used... eventually.
Most of the 100's of billions of dollars of GPUs that have just been sitting on shelves in warehouses and will continue to sit there for years even if there isn't a crash will be nearly worthless (relative to the prices paid) whether they try to mass liquidate at a small fraction of the purchase price to pay back some of their 10%+ interest loans they used to buy them or they sit around for a decade until there's a place to put them and at that point they could be so inefficient, they're not worth the money to install them and power to run them.