Game shows: why have the Big Three endured so long when others fail?

I remember the daytime game shows of my youth. Ah, the fond memories of everything from Classic Concentration to The Challengers. Today, with daytime syndicated versions of some modern upstarts lagging behind, only three have really stuck around for the long haul: The Price is Right, Wheel of Fortune, and Jeopardy. Note that only one of these is still on a network; the others are syndicated.

Why do you think this is? What do these three shows have that the others, from the Seventies/Eighties and the late Nineties, do not?

On a related note, the modern Price is Right has been hosted by someone other than Bob Barker before, but he’s such an institution on the program, could it survive when he finally retires or passes away?

Which is the only one still on a network? Price is Right?

I also don’t think PIR could survive with Bob. He’s a staple of the show.