Nissan did this and it sucks. Because dealers have to sell their vehicles too, so guess which vehicles get plugged in those stations? They are almost always busy.

Plus dealerships have business hours. I had a bad time once with an earlier Leaf generation trying to charge at night, in the cold. TWO quick chargers just a few miles away, both inaccessible.

Sure but it's not just about quantity. They need to be along the highways to be useful for roadtrips. And no one else even has the tech for supercharging at the moment, it's 72kwh supercharges vs 50kwh (rare) ( as far as I know ).

Various CCS charging networks have 350 kW chargers. For example, Ionity does (https://ionity.eu/) and Electrify America does (https://www.electrifyamerica.com/). Repsol has been installing 400 kW chargers (https://insideevs.com/news/375020/repsol-most-powerful-charg...).