Before the halcyon days of the internet, dealers were able to charge MSRP. Sometimes, they were able to charge over that, depending on how knowledgeable their customers were. As such, a guy at the gun show could sell a little cheaper, and gun shows seemed like a deal.
That's no longer the case, and most dealers are selling at a fraction over wholesale to compete. The retail side of the industry has hit a price floor that can't be beaten by the vendors at gun shows anymore.
Add to that the fact that one major promoter has been playing some games with pricing the last few years, and most major dealers don't see the point of attending. What's left are a few folks hoping to catch uninformed consumers, vendors selling freeze-dried food and survivalist weirdness, and private sellers.
I agree about the days before the internet, no doubt. Unfortunately, now they dont even try to come close to a decent price. I have never asked a brick and mortar store to beat an online price, but I do ask them to not charge me MSRP, or in some cases, over MSRP. Unfortunately thats the name of the game at gun shows anymore. More than anything its preying on the uninformed.