"Why?", you ask, Rich?
Well, my guess is that in the Good Ol' U.S. of A. the vast majority of people mistakenly "think" or at least "feel" that driving is a right, when in fact it IS a privilege!
And, because there are SO many people who forget this OR somehow don't KNOW this and would put up a big ol' freakin' fuss if they would be denied their licenses, the people at the D.M.V. offices throughout this country probably just figure it's not worth the trouble to fight these folks, and so they just go ahead and rubber stamp the whole process.
(...and THEN the whole issue of driving tests being pretty much a joke in this country ALSO might be a major factor here too, I'd guess...no correction...make that I'm SURE!)