It isn't a competition problem, it's a laws of physics problem. If you want to carry more traffic you either need more wireless spectrum or more towers. But "more towers" quickly devolves to the point that you would need a "tower" on every block, at which point you have nearly all the expense of a wired network and might as well run the cable inside the buildings.
We are talking about 35.46 gigabits per second. With 20x over subscription that works out to 20MBPS for 35,000 homes per tower. Or roughly a 200 x 200 home 'block' if everyone was your customer.
Alternatively, is your suburb is 0.5 homes per acre and 20% of people are your customers that's one tower per ~136 square miles.
Note: These numbers are not accurate for several reasons including directional antenna on towers etc but they give a ballpark.
DOCSIS 3.1 supports multi-gigabit speeds on coax. With actual fiber 100Gbps links are commercially available. For equivalent performance you aren't serving 35,000 homes per tower, it's more like 35. And a provider having a lower penetration rate doesn't save you any towers, they still have to exist and be operated by someone else in order for those people to have service. Splitting the market between more providers each with lower customer density would only make each provider's costs higher -- same total number of towers but now you each need your own spectrum.
