Most people don't have a choice for what ISP they use. And even when they do it's usually "do what to live in the modern world or deliver your packets via the Pony Express?".
You are right, but that's mostly a US problem. When I lived in Europe I was able to pick from a list of at least 10 providers. I'm not sure how it works, but I think there is a law saying that the ISP that laid the optic fiber cable must rent it to other ISPs