1. "the dealer is still involved and legally can’t be dis-intermediated in many states"
2. "In many cases it is a criminal offense for an auto manufacturer to sell a new car to anyone but a state-licensed car dealer"
The simple answer is that buying an automobile means dealing with a price-fixing cartel. The Internet hasn't fixed this process because it's legally sanctioned.
As a corollary, it's no wonder that even the tiny bit of competition from foreign auto makers caused the US auto industry to collapse. They'd had an oligarchy for decades, and they were utterly unprepared for anything.
Each of us has a moral right to buy and sell what we want from whomever we want. Advocacy can make this a legal right once more.
When I bought a new car, I used the dealer's website to study their inventory. Once I found the make, model and features I wanted, I used the "days on lot" number to negotiate a lower price. (Since, as I understand it, dealers make payments on their inventory; therefore, the longer the car is sitting on their lot, the more money the dealer has "lost".)
And when I bought used cars, using the internet helped save me thousands of dollars (close to $10K each time).
I've bought my last 2 cars off the internet and it was a really easy hassle free experience. I used zag.com both times. Let the dealers battle it out, pick one you're happy with. No need to go into the dealership, that's what a phone/email is for.
I was there maybe an hour to pick up the car. Of course they try to sell you the extended warranty and other stuff but they didn't push. A simple no and on to the next item.
The first one was a Mini for which the conventional wisdom was that dealers never discounted off of list price. I emailed every Mini salesperson within an easy day's travel with what I wanted to order and had a discounted offer over the phone within 5 minutes - within two hours I had a more convenient dealer match the price and throw in a few extras. First and only time I stepped on the lot was six weeks later to pick it up.
Last car I bought, I found online though AutoTrader with the options I wanted on Sunday about 120 miles away, but the dealer was closed. Called Monday morning 8am, negotiated the deal over the phone by 10am, and the car and paperwork were delivered to my driveway at 6pm that night.