The ratio of those two values shows, in my experience, that a lot of people are not very good at things they spend a lot of time doing, and are generally unaware of their own shortcomings
The average American spends 4.2 hours a week in the car. A typical 40 year old american has driven around 50,000 miles. For someone to continue to be bad at driving after that much experience, it must be a fundamental limitation on their capabilities for learning, thinking, or understanding. Drive to work any given day in Denver and you will see that a large number of people suffer from those fundamental limitations.
This article seems to present a world where most people the author interacts with can think critically about a complex topic, and are interested in learning or improving themselves. I wish I lived where the author lives, because I have had multiple jobs across multiple countries and never encountered an average population like the author describes.
(For what it's worth, I'm making this argument as someone who _is_ a bad driver, and that's a large part of why I don't drive anymore!)