> we know deprecation cycle of DC hardware leans towards tulips i.e. <10 years (very generous) vs 20+ years for fiber layout

[1] is a reasonable discussion of DC cost models, which calculates depreciation as part of the annual cost.

> here is the rest of the order magnitude more $$$ that justifies existing spent relative to time frame coming from?

That money comes from long term debt (ie bonds by public companies[3]) and new investment into neo-cloud companies (ie, IPOs like 4).

The justification comes revenue. Eg, the NScale IPO above[4] has $51B in long term contracted revenue with an annual run rate of $500M.

[1] https://epoch.ai/data-insights/ai-datacenter-cost-breakdown

[2] https://www.cushmanwakefield.com/en/united-states/insights/d...

[3] eg https://www.yondrgroup.com/newsroom/press-release/yondr-secu... (but you'll find lots of similar bonds issued)

[4] https://dealroom.co/news/143730-nscale-eyes-september-us-ipo...

> On a spectrum between tulip wilting and fiber build out, we know deprecation cycle of DC hardware leans towards tulips i.e. <10 years (very generous) vs 20+ years for fiber layout, a lot of which is actually infra/earth works etc.

Counterargument: As advancements in transistor densities slow down, the rationale for increasing depreciation cycles makes more sense. As the performance gap between new & 5-year-old hardware continues to shrink, then the need to replace older hardware similarly shrinks, justifying longer depreciation cycles.