It's a delicate ecosystem: the car salesmen need their cut to spend on drinking and gambling or else the bars and dog tracks will shut down causing more unemployment.
you can order a Ford Mustang Mach E from their website and have it shipped to a dealer and never really do anything at the dealers except get your new car
Because dealers have lobbied to have the law mandate them.
I know "deregulation" is a bit of a dirty word, but some regulations are genuinely bad. In this case, it's literal textbook rent seeking, in the economics sense.
I don't want amazon involved in anything, but I've bought a car off the internet before and had it delivered. I only had to to go anywhere to do the wire transfer at my bank.