Last mile infrastructure is always a winner takes all market.
Even if all the barriers to entry are removed, you won't have 20 different providers competing in a single city. Only 1 or 2 providers will survive. This is because operational costs for running your own lines will be constant, but you will always have only a fraction of the customers if you are competing with 20 other providers.
I've commented on this topic in a previous HN thread. But I believe the solution to the problem is a bidding system. Companies bid to build infrastructure. And companies bid to maintain it for short period of time (3 years).