A part of the equation I don't see anyone else putting is that for the broadcaster in existing networks/region it is relatively very cheap to operate. IIRC the total cost for the over-the-air broadcasting would for many markets and stations would essentially be a rounding error and easily still make a profit.

On this point alone they would have to REALLY drive down the numbers hard for them to not even bother, and even then it would more likely just see channels in smaller regions merge or let the broadcast from the larger region take over for a long period.