A fatal accident can cost a trucking company over 1mil USD. The ATA (American Trucking Association) lobbies heavily to allow under 21-year-olds to carry freight over state lines. There’s no talk about in the upper echelons of US trucking to relax medical, drug, safety, or experience requirements; these companies know it will put them out of business if they hire drivers who get into accidents or even get people killed. There is currently a HUGE lack of qualified, safe trucker drivers in the US. Your suggestion would drive up the cost of freight in the US, and would cost lives.

Further, companies like Amazon will have enough money and influence to absorb the cost of unsafe drivers, while most registered US motor carriers (the vast majority of which are under 100 trucks) will be put at a huge disadvantage vis a vi Amazon. The last thing society needs is Amazon yet again pushing others out of business by being able to race to the bottom and lose money in the short to medium term.