I would argue the heart of the problem- or at least a major component, is that so few companies control the market. I can go to a different grocery store if the prices are insane at only the nearest one. However, pretty much all grocery stores carry mostly the same products. Those products are owned by just a handful of companies.

Want a different cell service? There's just 3 companies left. Internet? You probably don't even have a choice.

It's pretty easy to jack up prices if there are no competitors left to swoop up your customers.