I think your assessment is a bit premature. GB is very definitely an acquired taste, and while he may be very successful with his online 'channel', it is not a given that his channel on regular TV will be a success.
I know of one radio personality that gets huge audiences, has an 'online' version of his show also available that is doing quite well. Yet when he was on TV he was a dud and didn't last long. That person is Rush Limbaugh.
But we do have his ratings over the 2+ years at Fox News and those numbers at 5 PM were impressive to say the least.
Even with the decline, over 2 million viewers in Feb. 2011 still took everybody else to the cleaners, including nearly every other news/opinion show in prime time, not just at 5 PM.
Based on that, I think it's safe to say that he will have very respectable numbers on Dish and the other multichannel providers as he launches on them. And this is not just 60 minutes at 5 PM and it won't be just opinion programming. He mentioned just yesterday that he wants to "fast track" a Nightline style show to air this fall and run at least though December. He also hinted that a hard news show is in development.
So time will tell if this is really a good move and if GB can have the success he now enjoys as an online personality as he moves back into TV. His Fox departure was not wholly his decision as he was costing them ad money.
He wasn't costing them revenue, the leftist ad boycott was. It will be much harder to do that this time around. It is and will be an interesting journey to watch.