Having seen more than a few episodes of "Pawn Stars" (my dad is a fan), I have to defend it as being a perfectly good history show (I can't speak to the others). Although the premise doesn't seem to have anything to do with history--watch people sell stuff to this pawn shop in Las Vegas--if you actually watch the show you'll find that almost everything it shows people selling has something to do with history. A lot of the time, it's the usual "guns and Hitler" type of things--old guns, artifacts of different wars, and the like--but just as or even more often it's cultural artifacts. Posters for once-popular, now obscure movies, for instance, or old and rare bicycles. And in pretty much every case they have some kind of explainer segment that goes over the historical context of this artifact--this director was on fire at the time, for instance, or this gun was used by the doughboys in World War I, or so on and so forth. Sure, there's stuff that doesn't have anything to do with history, showing the "behind-the-scenes" working of the shop, but that's just interstitial material, stuff to pad out each episode and keep it palatable for the average viewer.
In other words, it's just the kind of thing that people here should, theoretically, like. It's a history show that's palatable to the everyday person, which presents information on a lot of unknown or obscure subjects, and with a big focus on cultural history, simply by the nature of the things people tend to collect and sell. It's everything that people who used to criticize the History Channel for being the Hitler Channel wanted. And yet those self-same people now criticize the History Channel for presenting this one. They just can't win.