In order to determine automobile insurance premiums for a driver, insurance companies calculate various risk factors; as the risk factors increase, so does the premium.
Conclusion (Yet ... should)
Insurance premiums should increase with frequency with which a person drives.
Evidence (after all)
The more you drive, the higher your chances of being involved in a mishap.
Evaluate
The sentences leading up to the Yet pivot seem to just give us the background on how insurance policies determine their premium rates.
The more risk factors, the higher the premium.
So how could we possibly counter this argument.
Given that ... driving more frequently increases your chances of getting into an accident, How could we still argue that ... premiums shouldn't increase with more frequent driving?
We'd probably have to argue that people who drive a lot do have elevated risk because they're on the road more often, but maybe something else is different about them that reduces their risk.
What if the people that drive a lot tend to ... - be better drivers - drive safer, better-maintained cars - drive on safe, more-isolated roads etc.
Goal
Let's look for something that's suggests that people who drive are more have some reason to also be considered a lower risk, thus we shouldn't increase their premiums just because they drive more.