The dealers that treat people the best will normally get the most traffic. People talk, just like on this forum, and make recommendations based on their experience. If there is a dealer that people feel is not good to deal with, they will either go out of business, or change their ways. With so much communication between consumers now, the day of the sleazy dealer may soon end. At least, they won't remain in business very long. I have no problem with that, whatsoever.
Yes, it is up to each of us to do our research. There are many posts on RV.net that chastise buyers of RVs or tow vehicles for buying a unit that does not fit with their opposite side of the hitch - too much weight, too little capacity. That was due to lack of research.
Buyers of anything, if they want to be sure they have the right product at the right price, need to do their research. The less research done, the greater the likelihood of a bad deal. Not the fault of the dealer. If you found an employer willing to pay you 10% more than the market said your skills were worth, and you were looking for a job, would you turn them down? Doubt it.