> I've also seen counties offer tax incentives. Why? Just have them pay property tax.

This seems naive. You are missing the point. If you don't offer tax incentives, then you don't get data centers (or other important industrial facilities). The internal United States market competition to attract these projects is intense. If you look at when a major foreign auto manuf wants to build a new plant in the US, there is a line of communities hat-in-hand offering all kinds of tax rebates and cheap loans.

    > Loudo[u]n County gets half of all its revenue from data center property tax. Its residents were already rich, and now their local taxes are artificially low. Who wouldn't want that?

I looked up the reason why Loudoun County has so many data centers: (1) favorable zoning laws passed in year 2000 and (2) sales tax break specific to data centers.