Your take seems a bit optimistic if we use the dot-com boom as an analogy. The dot-com boom sped up a massive infrastructure build-out, but also left damage that lasted for a very long time, with many organizations collapsing, and others taking a very long time to recover (e.g. cisco networks). It also seems that these 'data-centers' have a higher depreciation rate than 'dark-fiber' did post-dot-com, which means that there is likely to be greater capital waste.
I am not sure whether the dot-com boom was a net-positive, and the AI boom may be less productive.
My point is that these hyperscalers need X traditional data centers and Y AI data centers. If Y goes to 0 that doesn't mean they eat everything they've spent on those data centers. They get converted to serve non-AI loads while other older ones get abandoned or leases not renewed and so on.
In that scenario the GPUs are a loss. But really at this point inference is so profitable it's hard to imagine these data centers not being able to at least cover operations & rent.
A lot of the dot com failures didn’t spend on massive infrastructure, they just burned through cash on salaries and expensive chairs.
They were underpants gnomes who had no realistic way of making money.
Cisco networks took a very long time to recover, but in the meantime, everyone else enjoyed massive growth in cheap connectivity.
Capital waste is only capital waste if the physical goods that were built are no longer useful for anyone. Otherwise, it's only a waste for the people who lent money.
It absolutely was a net positive. On the infrastructure side we got datacenters built and tons of dark fiber put down. At the start of the boom we had only 2G cellular for goodness sake. I think you could argue we wouldn't have necessarily had the rise in cloud compute without some of the 'overbuilding' of datacenters in web 1.
For reference this 'massive build-out' resulted in, according to a Berkeley study I found, 500MW of total datacenter power in the US across 320 locations at end of 2020. This wasn't too much for very long: as of 2005, according to Tier1 there were 511 datacenters. And it was likely only really a year or two: Dupont's VA3 utilization numbers published it at 50% utilization in 2003, 89.4% in 2004, then full thereafter.
Meanwhile, these infrastructure improvements allowed, for example, things like the iPhone to be built and deployable -- there was 3g, there were a LOT more web devs that could create the early (web only) apps the iPhone needed to compete. This in turn allowed another round of investment to be built on top of all of that.
On the capital side, investors were also able to buy Amazon at around $1 / share. AAPL at iPhone launch was $7/share. I haven't split adjusted either of these, this is just from memory.
I don't think a bust was necessarily good but the boom undeniably built out infrastructure, a small fraction of what the world is currently using, and did it pretty quickly, and then post bust that infra got bought out in a capital efficient manner. I think that's the bear case here.
Put another way, the Dotcom one boom was wrong about two things: timing was too fast, and the predicted scale of change was way, way, way too small. They undersold the future.