Have you noticed the massive amount of money the competing car companies spend on advertising? Have you ever suspected collusion when you shopped for your own car insurance?
Why do you think people are reluctant to switch? Perhaps because the market is so competitive that there really isn't much difference between the offerings?
I don't switch because it's a pain to even try. I've had experiences in which a price I was quoted turned out to be lower than I was actual billed, so I don't have a lot of confidence that I'll get a straight answer if I do ask for quotes for new companies. I'm not sure I have accurate answers for questions they might ask. So I keep paying whatever, even though it's more than I like.
For all I know, I could be paying half as much elsewhere. This is just the company I've been with for many, many years.
Yes, it is a multidimensional competition. Price is not the only variable.
So is service when you make a claim (I've been "screwed over" twice when making car insurance claims). And so is obfuscation of services provided. So is money spent on advertising. And lobbying.
All insurance companies compete with a unique strategy on the mix of variables.