My best guess is this is a contract thing. Sirius's contract with Howard is valuable because it limits his rights to be broadcast anywhere else, with some exceptions. I'm sure the old Howard inDemand/HowardTV was one such exception...but that exception was probably specific to that inDemand service. In other words, the contract probably doesn't allow Howard to distribute his show on any new service. What is allowed seems to be just promotional stuff on his website and social media platforms.
But it goes both ways. When Sirius came out with a smartphone app in '09, there was no Stern Show because it would've violated some contract provision.
But it wasn't until he re-signed his latest contract in 2011 that it became available.
The iPhone and smart phone apps (as we know em today) weren't invented until '08, 3 years after he started his original contract with Sirius. Chances are Sirius didn't obtain the right to play Howard on a smart phone app--they didn't even know it existed. So Howard didn't give them permission; my guess is Howard decided to wait it out and use that right as leverage in negotiating his second contract.
As for the new HowardTV, he's clearly putting a ton of effort into filming the show. He's filming what goes on in the studio, and it's really high quality based on the clips from his youtube channel. And he's got someone editing and directing it. I don't know if there will be any budget for much new behind the scenes stuff, but it seems obvious that some online service (or even his website) will host it once his current Sirius contract expires.