I think it would create a sort of a monopoly -- the municipal taxes paying the ad-free tithe. I imagine corruption and backroom deals would result in that cost

I think it would create a sort of a monopoly -- the municipal taxes paying the ad-free tithe. I imagine corruption and backroom deals would result in that cost going up and up over time. A better solution would be to outlaw ads / billboards, and ticket the offenders to offset the lost income from billboards etc. Municipalities love new revenue streams.