Drivers ed basically ended in the 1990s, so everyone younger than me did not get it. Then of course there are drivers getting older and losing skill, and nobody ever takes refresher courses, so I am quite sure the average driving skill level has been dropping since drivers ed was ended in most school districts.
My hometown school district still offers drivers education, and some places, like most school districts in urban Colorado, have never had it. The skill testing in order to receive a license didn't change in those places where it wasn't a rite of passage. Enter the for-profit driving schools. One of the memories of looking through the Denver phone book in the library when I was growing up was the amount of driving schools--a completely foreign concept to my younger self--in the Yellow Pages, including enterprises such as the Sears Driving School ("Use your Sears Card") and the Montgomery Ward Driving School.
We still have a few down here, but not like it used to be. The big plus was/is the ability to get a full license at 17 insted of 18, as well as the insurance discount. I think the defensive driving courses are pretty popular, since they can save a good chunk of change, but at the same time, there are dangerous distractions like phones that didn't exist like they do now.
Many states are now going to a graduated license model, with privileges that increase over time and phasing in the elimination of restrictions, most notably the prohibition of multiple passengers--especially those not related to the driver--for those without an unrestricted license.
Insurance companies and technology have also played a role. Only the affluent can afford to insure a teenage driver without evidence of an approved training or safety course, particularly if the vehicle insured isn't a clunker. Many insurance companies will only give their best rates to those drivers who consent to an OBD module in the insured vehicle which measures speed, braking deployment and overall driving patterns. The continuing education in this model is via feedback in the form of possible lower rates for changes in driving behavior (or possibly policy cancellation for persistent violations).
Anecdotally, the younger drivers I've observed are generally conscientious and follow most established rules-of-the-road, including proper use of turn signals (a big pet peeve of mine). As a pedestrian, I've almost been hit twice in the past month, and neither driver was under 25.
The drivers most likely to cause a problem seem to be those who are new to the local area (especially from where aggressive driving is the norm), those with showoff vehicles (and it's no longer sports cars as it was when I was growing up), and those who experience most of their life inside a vehicle (not only the salesperson closing deals while driving, but amateur beauty operators, amateur social workers to friends and family, and drivers who are focused first on their mobile entertainment system).