[lotsofpulp]

This discrepancy happens because insurance works well for unknown risks that are independent from the entity being insured and for uncorrelated events. Similar to healthcare, vehicle collisions are highly dependent on the driver, and so some of the risk is not unknown, and hence can be priced.

Pretending you don't know the risk factor when you do (perhaps in the name of fairness) can also cause problems.

[aianus]

The low risk group (older, married, men and women) are the best positioned to absorb a rise in premiums so I'm not sure what problems would be caused.