I live in a community of 60 households (clusters of duplexes a little outside of town, rather than an urban highrise) and we have run our own internet service here for 15 years.
We started with some cheesy radio links and have moved up in speed over the years to where we now have a direct fiber connection to a local ISP. We are currently buying 50MB symmetrical service for data, and that is sufficient to allow widespread streaming of Netflix for our residents (we don't have access to cable TV here, but a few folks have satellite). We added VOIP phone service a few years back, which the same ISP sells us over a separate set of fibers to avoid call quality issues. We have local servers for email, community website stuff and for the VOIP service (using the excellent SIPx open source software). We use open source PFSense software running on a low-power ALIX box as our central firewall & DHCP server.
We charge $30 for Internet and $30 for phone, with unlimited domestic long distance, which includes a small margin that allows us to accumulate funds for maintenance and improvements. These prices are considerably lower than people here would pay for equivalent services, and people are pretty happy with the quality. The system is maintained by a small team of volunteer geeks, and our residents understand that we won't necessarily jump out of bed to fix a problem--we'll do the best we can, but don't guarantee 100% service levels. We don't enforce any bandwidth caps per-household, and that has not been a problem.
This kind of thing is entirely feasible, as long as you have a core group of geeks that consider it something they are interested in putting some time into. We have saved our residents many tens of thousands of dollars over the years, keeping that money circulating in our local community instead of shipping it off to some corporate behemoth. And for those of us who do the work, we generally find it an engaging and enjoyable use of our time, and find it satisfying to provide a useful service to our neighbors.
Oh, and I concur with an earlier poster--if you do it, do it wired. Provide one jack to each condo, and let the owners distribute around their rooms as they see fit. You might provide some wireless access in common spaces.