Theres still locations here that can't get fiber. The local hospital is owned by a church and they own apartments adjacent to the hospital. These apartments are surrounded by others that get fiber but the map still shows they aren't planned.
There are a few apartment complexes around Longmont that have resisted integration with the city's fiber network. My understanding is that the city has negotiated with each of them over the installation of fiber on their premises and that some of those negotiations didn't succeed, e.g. the apartment complex owners wanted to own and control the fiber that the city would pay to install.
But this rings true. My building has some sort of an arrangement with Comcast. It's only Comcast and AT&T that are there right now. They pretend to work with other ISPs I bring in but usually cite "something something safety" and prevent them from setting it up. I have given up for now since Comcast has got the price down to $50 for a 75Mbps line for me.
Point is, while I don't know how and can't confirm, I have a strong feeling that Comcast pays off landlords somehow.