Tesla is leading the way today (somewhat painfully in some areas) but they're not the first to try fixing this. GM's Saturn tried to make buying simpler in the 1990s and surely there were other previous examples, too.
Ford seems to be testing the waters about how to simplify the car purchase process: https://fordauthority.com/2022/05/ford-dealers-will-likely-s...
There's plenty of dealerships who have historically had simple purchase processes with standard no haggle pricing but often buyers have to do extensive research in order to find such dealerships.