I can't imagine why it isn't done . . . except that everyone assumes that it would go the way of the suits against the IRS . . .
I'd sure like to see it done--as the above link clearly shows.
As to the FCC, they appear to operate under the commerce clause, that's why you see the pirate stations raising such a fuss if they are careful to design and aim their antennas to not cross state lines, and then still get harassed by the FCC. Of course, some folks in the past I have read have tried to beat the full auto regulations by designing and manufacturing and distributing completely intrastate, the feds don't allow that to happen, either. Laws are written for the people, not the law administrators.