The closest analog to Nvidia from the dotcom bubble is Sun Microsystems. They make the expensive hardware that are the shovels in the gold rush and will see reduced sales if build out exceeds user demand.
However this doesn’t diminish the need for their hardware in the long run. What killed Sun was Linux. Demand for internet services rebounded but not their costly servers.
That’s the real threat to Nvidia. That the future is Google TPUs or Groq’s LPUs not that OpenAI can’t come up with $1.4T.