Surely this would be a safer way of ensuring drivers are competent?
If they fail then it would prompt drivers to correct any bad habits they've slipped into, and makes more sense than doing one test, possibly as a teenager still, to assess a lifetimes worth of driving.
I know 2 people who I'm sure must have passed by fluke, one older family member has told me shes regularly in the wrong lane as the signs confuse her, and is often saying about being cut up etc.
And someone else I know has had 3 near accidents and written his car off within the last year, surely more regular testing would pick up drivers like this needing some extra support.