It might not even cost the county tax assessors much, some of these abuses are so blatant that even a private citizen could buy out the building under that policy:
https://dailycaller.com/2018/08/14/apple-hq-200-dollars-sant...
> Apple, history’s first trillion-dollar company, is arguing that a cluster of new buildings at its headquarters is worth only $200 in order to lower its tax burden.
> The trillion-dollar tech giant claimed in an appeal the value of the “cluster of properties” is worth $200, not the $1 billion value given by the Santa Clara County’s tax assessor — elected officials who determine property value for tax purposes.
I'd call it "disruptive innovation" to buy out Apple's headquarters buildings for the $200 it thinks they're worth, rent them back to Apple at the maximum price the market will bear, and pay Santa Clara County it's fair share in taxes.