The problem is that in many cases, the common folk in a town have to pay at least somewhat for the municipal broadband even if they do not use it; so it'd better be worth using.
I can understand municipal cable conduits and such, since they are somewhat analogous to the roads; but when your municipal government is actively excluding competition (Comcast in this case, if the title is anything to go by), they had better make sure they municipal cars on those roads are good; because if you don't like them, your only recourse is generally to leave town.
To satisfy the "better than Comcast" requirement, generally speaking the only thing you need to do is stop excluding their competitors. Comcast is actually pretty reasonable in competitive markets; but when a satellite internet company needs specific permission to operate in your county, that's something you can fix right now, with no investment, and immediately gain some competitiveness in your ISP market.