My US driving test didn’t even include a highway drive. It does feel like the ability to drive is treated as a right here. It’s only a privilege from the license cost point of view.
I think this is because actually driving on freeway is actually easier that on streets, the major difference is that if you get into an accident likely much more severe. And you're much more likely to get into accident during a test than after passing it.
What one needs on freeway is to have a greater confidence in their driving to not do sudden changes and drive around the same speed as the rest of the traffic. That confidence you get after you pass your exam and drive for a bit.
The only country I've heard of where getting a basic driver's license is remotely hard is Germany, and it's because of the Autobahn. I forgot the details but I think you have to take a long class and clock a certain number of hours, and pay a couple thousand dollars equivalent. That kind of crap simply is not necessary in 90% of the US which is slow suburban traffic, where people can live for years without even going onto a highway once.