Not sure I would jump to that conclusion regarding all dealerships.
I've had great, good, fair and downright awful (as in trying to cheat me financially) experiences with dealerships over the years.
They are NOT all the same, and it doesn't seem to matter which manufacturer it is either.
There are good and bad dealers across all makes.
It comes down to how the business is run. Don't paint them all with the same brush.
I had a great (Nissan) dealership go down the toilet when it sold out to another owner, and the new owner changed everything and everybody.
The secret seems to be in finding a good dealership, and then developing a good relationship with them.
In the case of my Mazda, I have not set foot in the dealership building where I bought it, and they have not bothered contacting me with any kind of followups in over two years of ownership.
I have taken my car into another Mazda dealer closer to me for service, and they have been excellent, so that's where I will continue to go.
Cheers everyone.