How can they? Won’t dissenters offer policies without?
By “they”, I guess you mean IIHS. They are all the insurers in the USA, essentially. Auto repair or replacement costs are low compared to bodily injury costs. The insurers have lower payouts with safer cars, you pay more because the cost to buy them is more, and they charge you more on a higher priced vehicle. Now, what insurer is going to kick that golden egg into the gutter?
The cost to buy an insurance policy is the price the insurer offers. When I’ve shopped I’ve received estimates more than twice the cheapest. They aren’t colluding to fix prices.
For liability insurance?
Market participants?
I looked at saw blades today. Some were $10 and some were $40. Market forces at work?
Saw blade vary in quality, hardness, durability, by large amounts.
I rest my case. So do insurance policies and companies vary, and some are mutuals like co-ops.