They won't test everyone on a regular basis due to the cost and because it would be politically unpopular. Heck, I saw someone in their 30's go ballistic about losing their license after having two seizures while driving (both of which resulted in collisions).

Enforcement is another issue. I don't even bother reporting being hit by cars anymore because the police refuse to do anything about it. That is after an incident and with a plate number. Enforcement of people driving without a license would be next to impossible unless there is an incident.

As for "don't bother looking", well, you cannot really test for that since it is usually the result of some form of distracted driving or carelessness. Both of which are unlikely to show up when someone knows they are being assessed.