Actually, because of modern technology, they are probably safe for decades.
In the shadows of Houston's TV towers (Missouri City) the Fort Bend Toll Road cuts through this section that will never see homes built up within the falling radius of those towers.
Ah yes. And when the towers finally become obsolete because of wide spread use of internet based information transmission... what then? Jed or somebody is a millionaire.... again.
Nothing is static. The world is always passing even the passive by.