I don't think the parent was specifically referring to hardware alone. The 'rails' in this context are also the AI algorithms and the underlying software. New research and development could lead to breakthroughs that allow us to use significantly less hardware than we currently do. Just as the dot-com crash wasn’t solely about the physical infrastructure but also about protocols like HTTP, I believe the AI boom will involve advancements beyond just hardware. There may be short-term excess, but the long-term benefits, particularly on the software side, could be immense.
That's my big worry. The Internet was made with an idea of being a common. LLM's are very much built with mentalities of trade secrets, from their data aquisition to the algorithms. I don't think such techniques will proliferate for commercial use as easily when the bubble bursts.