Internet in Chicago is unregulated; it's a completely open market.
Many years ago, people got really tired of companies digging up roads, putting in utilities and then repaving the road, only to have some other company come in and dig up the road again a few weeks later. So the city now has an ordinance - if you are going to dig up the road, there has to be an advance public notice, and anyone can lay utilities once you are done but before you've repaved. And once you've repaved, there is some time limit before anyone is allowed to dig up the road again. This makes it pretty cheap to lay dark fiber that will someday get lit up, and now Chicago is reaping the benefits.
Yes, the HOA signs a contract and makes the payment, and then adds the per-unit fee to the monthly assessments.
These small local ISPs are super efficient - they concentrate on infrastructure and support, with 1 or 2 people for sales and billing: one sale equals hundreds of customers, and hundreds of customers equals a single payment.
Thanks. I looked at doing the same but got scared off as I wasn't sure about how practical it would be to keep up and running. Maybe I should try harder again. :)