Let's be realistic, how many people are really willing to pay for DSPs that aren't for a show that they went to? I may sound cynical, but I don't think very many are.
Most people only go to one show a tour. And out of those people, I'm sure a lot of them don't even know about the DSPs. And even if they did, they'd only buy the show they went to. The 20 LPL users (and that's a generous estimate) who might pay for multiple shows probably isn't enough to justify all the work I'm assuming goes into releasing DSPs.
All I know is, whenever a show with something cool was released on DSP in the past, there'd be a ton of posts/tweets asking if and when it would be in the "usual place." That's part of the problem. We needed to pay for it. And it sucks for the people who DID pay for multiple shows, because they did their part. But I don't think enough people did.