For reasons of safety?!
Also seems to assume license testing is standardized with rigorous instruction regarding safety.
Some states don't require anything more than successfully completing a multiple choice test about signals and signs many folks end up ignoring anyway, and a brief on road exam.
People go in and drive safely for the 20 mins their subjected to a road test and sink into bad habits all the time.
I personally saw a wobbly 75 year old man with shakey hands (he updated his signature wearing coke bottle thick glasses) and a cane get his license renewal rubber stamped
Feeling safer already.