Many of legacy systems still running today are IBM or Solaris servers at 20, 30 year old. No reason to believe GPU won’t still be in use in some capacity (e.g. interference) a decade from now.
VS plurality of AI investment, i.e. trillions are going towards fast deprecating components where we can say with relative confidence will likely be net negative stranded assets in terms of amoritization costs if current semi manufacturing trends continues.
Keeping some mission critical legacy systems around is different than having trillions that makes no financial sense to keep on the books, i.e. post bubble new gen hardware will likely not have scarcity pricing or better compute efficiency (better apex and opex), there is no reason to believe companies will legacy GPUs around at scale if every rack loses them money relative to new hardware. And depending on actual commercialization compute demand, it can simply make more economic sense to retire them than keep them going.
TLDR old durable infra tends to retains positive residual value because they're not easy to replace economically/frequently, old compute has negative residual value because they are easy to replace economically/frequently.
Even if all of the GPUs inside burn out and you want to put something else entirely inside of the building, that's all still ready to go.
Although there is the possibility they all become dilapidated buildings, like abandoned factories
Of the most valuable part is quickly depreciating and goes unused within the first few years, it won't have a chance for long term value like fiber. If data centers become, I don't know, battery grid storage, it will be very very expensive grid storage.
Which is to say that while there was an early salivation for fiber that was eventually useful, overallocation of capital to GPUs goes to pure waste.
Maybe it's cheaper if we measure by dollars or something, but at the same time we lack the political will to actually do it without something like AI on the horizon.
For example, many data center operators are pushing for nuclear power: https://www.ehn.org/why-microsoft-s-move-to-reopen-three-mil...
That's one example among many.
So I'm hesitant to believe that "electricity is a small cost" of the whole thing, when they are pushing for something as controversial as nuclear.
Also the 2 are not mutually exclusive. Chip fabs are energy intensive. https://www.tomshardware.com/tech-industry/semiconductors/ts...
AI companies are saying they are trying to build nuclear because it makes them sound serious. But they are not going to build nuclear, solar and storage is cheaper more flexible and faster to build. The only real nuclear commitment is Microsoft reopening an old nuclear reactor that had become uneconomic to operate. Building anything new would be a five+ year endeavor, if we were in a place with high construction productivity like China. In the US, new nuclear is 10 years away.
But as soon as Microsoft restarted an old reactor, all their competitors felt like they had to sound as serious, so they did showy things that won't result in solving their immediate needs. Everybody's renewable commitments dwarf their nuclear commitments.
AI companies can flaunt expensive electricity at high cost for high investor impact precisely because electricity is a small cost component of their inputs. It's a hugely necessary input, and the limiting factor for most of their plans, but the dollar amount for the electricity is small. The current valuations of AI assume that a kWh put towards AI will generate far far more value than the average kWh on the grid.