Yea, Fios is only available in a few buildings. A decent part of it is that TV franchises are done on a town-by-town basis in Massachusetts and Verizon only wanted to build Fios where they could also sell TV - and then Verizon found out that their fiber business had poor economics even with TV service and backed out of a ton of their fiber builds in New York and New Jersey.

I think a lot of wired providers found the economics to just be poor when challenging an incumbent. RCN went bankrupt in 2004, 10 years after being founded. It hasn't really expanded its coverage in recent memory and is now just owned by a private equity firm via a leveraged buyout.

On the plus side, it looks like maybe the economics are shifting. AT&T has announced that they're going to be doubling their fiber footprint over the next couple years. Verizon isn't doing anything nearly that ambitious, but they are looking to grow their Fios network by 9% over the next 3 years. AT&T seems to have a difference of opinion on the economics of fixed-wireless vs fiber compared to Verizon. AT&T has said that fixed wireless isn't going to be a big part of their strategy and that the cost to serve customers with fiber is better, but some of that depends on how much data you're expecting customers to use. Verizon seems to disagree and is planning for their fixed-wireless network to cover 2.8x more households than Fios (with a very minimal investment in Fios expansion).

It's hard to compete against an incumbent and invest in a new network where you might only take 30% share. I know, everyone thinks that the whole world would jump on fiber just because they would, but it's hard to take marketshare and with something like Fios, you'd often need a landlord to approve having it installed. RCN has been in Somerville for many decades and can easily hook up most residences without the landlord being involved because they'll use the same coax that an existing cable connection would use (and they can just disconnect the unused Comcast line outside the building). With Fios, you're talking about installing an ONT (optical network terminal that converts the fiber to something usable inside your home) in the basement and then running ethernet from there or trying to use existing coax wiring with MoCA - but a lot of buildings in Cambridge don't even have coax running inside the building because they just made penetrations from the outside on each floor - back in the day for cable TV and back when these buildings weren't worth much during the white-flight era of cities.

In Somerville, RCN has about 27% of the market while Comcast has 73%. Yes, RCN isn't fiber so it isn't really a superior product, but people truly hate Comcast and RCN can only achieve 27% - and RCN has the advantage that they can easily disconnect Comcast on the outside and swap their connection in while Verizon would have a lot more work to do.

That's not to say it can't or shouldn't happen. AT&T is making a huge bet on fiber over the next couple years and they even talked about moving into markets beyond their wireline footprint in select areas where it made economics sense past that. That said, it is hard to compete with incumbents.