Given redundancy and inventory logistics, once your industry gets to some number of billions of dollars of equipment, you're goddamn right there's going to be a billion dollars worth of equipment lying around. It's not the magnitude, it's the ratio that you should get upset about, if there's even anything to get upset about.
There's also rates of consumption versus rates of production. If consumption rates are variable (eg, ramp-up to Black Friday), there is only so much variability I can manage in production. I can produce at a mostly-stable rate all year and let inventory accumulate during slow months, or I can improve my variability, but the cost is more complicated management of people, and increased likelihood of late surprises.
Also, don't data centers collide with public sector timelines? If you have to start building a data center by November 1 and you try to get your approvals all to happen on October 31, you're going to fail, and possibly get fired.
You try to line those up ahead of time, maybe break ground before the next election so they can't stop it, or someone else sucks up the surplus grid power in that substation. If it's built early, it's sitting around waiting for demand to use it. But at least you have it.