One has to wonder… Why doesn’t a single company just roll in and offer unlimited mobile data and shake things up? Oligopoly is the word you’re looking for, a handful of companies (ie the “big three”) operating together like a single, corporate monstrosity known as a monopoly thanks to the popularized board game

I have to slightly quibble and disagree here. The reason we have high prices is because of the oligopoly, but the oligopoly is not the reason (or at least not the main reason) that another company doesn't sweep in and shake things up.

First of all, the reason for that is partly regulatory. The Canadian government has mandated Canadian ownership rules for our telecom networks which prevents a larger (American or other international firm) from coming in and sweeping out our existing telcos. While some would rather AT&T or Verizon come in and replace Bell or Rogers, the reality is that they're not going to grow the market meaningfully and they'll pretty quickly conglomerate together or buy one another up like they've already been doing and we'll be right back to our existing status quo. On top of that, those ownership rules do also have a national security argument behind them, people would be much less pleased if a national scale telco was owned by Saudi Arabia for instance.

The real reason for the oligopoly in the first place though is that building out telecom networks, be they fibre or wireless, is expensive, and the costs scale downwards massively with a greater customer base. It costs a lot to build fibre out to a neighbourhood to serve one home, that same build is dirt cheap if it's serving 100. In Canada, we simply do not have the density to economically support multiple competing high quality telecom networks. In Toronto, the highest density spot in the highest density region, we still only have a single fibre to the home provider (Bell), and it's only in the absolute highest density points (new build high rises) that we see Beanfield show up as a true fibre to the home competitor.

The fundamental economics of telecom networks does not support a scenario where we have 4+ fibre competitors in the same geographic area, meaning we will never have true competition between them. That is why the only way to avoid an oligopoly is to nationalize (or provincialize, or municipalize) the actual fibre infrastructure and create a virtual network provider market on top where the barriers to entry are low enough to get a lot of competition.