I think the high-density data centers that are being built to support the hyperscalers are more analogous to the dark fiber overbuild. When you lit that fiber in 2015, you (presumably) were not using a line card bought back in 1998.
Everything in that data center is depreciating as soon as they turn on the power.
AC, ups, generators not to mention the severs.
That's the thing with fiber it was still useful. The cards at either end are easy to add, waaaayyy cheaper and higher perf (they're were no cards on end of dark lines) 15 years later.
