The internet and wrestling, I think it gets too much credit as to what you're talking about. It's like the old argument that some people used with why Smackdown's ratings have historically been shit in comparison to Raw. It's not because the results of the show are on the net days in advance, it's because the show is treated like a C show with no importance and on a bad TV night.
The IWC is still small IMO. For the most part, whenever WWE (or even TNA for that matter) decide to throw in some worked shoot, inside type stuff, it almost always goes over the head of the live crowd. Plus, usually, the folks who fill up WWE arenas on a weekly basis are not smark marks, they're families (especially these days).
Of course, when they run places like MSG, Chicago, Montreal, Philly, those types of spots, you get more of the IWC crowd, but even still, I assume it's more of the vocal minority.
If anything, the popularization of the internet should mean promotions have greater means to make some money. Still, the bread and butter of WWE is TV driven, and while I'm not sure how effective they are with turning social media into actual dollars, I look at it as an untapped market (with WWE up to this point at least).
No idea about the other groups, but even then, it's cheaper to get word going on the internet then it is buying up TV spots in different markets I assume.