This isn't quite the same issue as NN, but in Seattle we had a single ISP monopoly (Comcast) until quite recently. Centurylink has started offering fiber in the last few years, but before that there was an uninterrupted decade where Comcast was the only viable broadband option for most homes.
(A number of vendors offered DSL, but it was extremely slow and typically not price-competitive; a small number of vendors offered very fast internet, but only in condos / apartment buildings in or near the downtown core.)