I does not. In fact, it explicitly assumes that the risk depends only on the car - insurance on a 500bhp car will be a lot greater than the one on a 100bhp car, even if the owner of both is a 50 year old lady with a perfect driving history. As I said - the law guarantees that the insurance cannot differentiate between drivers, so letting your 18 year old son drive your 500bhp range rover has no impact on your premium.
Tbf - it self regulates to some extent. My dad wouldn't let me drive his car, because he knew that if I crashed it he would lose all of his discounts and pay a lot more. So even though I technically could drive his car and be insured, he wouldn't let me as that was a financial risk to him.