But fiber optics are different, they stay good for a very long while and you just need to add better transceivers at the ends to upgrade them, it's questionable whether the current GPUs are even worth powering up once 2nm ones are out, and we also don't know how long they last, electromigration might start killing them in 5 years.
GPUs might become obsolete after the AI bubble bursts, but tons of supporting infrastructure, including non-GPU servers, will be in the market for pennies.
Yes, this bubble is much better than crypto/nft. Same as mentioned railroad rush - capex burned, but lots of stuff have been built and left after burst.