I'm personally un-sympathetic to Gary's plight to keep his work super secret. This feeling started when I found out that he asks conference organizers to NOT share the recordings of talks he gives. I'm not sure how often this has happened, but it feels against the spirit of presenting against these events.
If I've gotten something wrong, I'm sure someone will correct me, but those are the facts as I see them today.
Second, many many people have tried to build screencasting businesses. One of them turned into an 800 lb gorilla. Most of the rest don't exist any more. AFAIK, DAS was the second subscription-based screencasting company to exist, with the only prior art being a short-lived subscription option offered by TekPub (which was later acquired by the 800 lb gorilla). DAS still exists today, is still independent, and is still (almost) my only source of income, while dozens or maybe hundreds of others have come and gone. I'm sorry if you don't like the way I exercise control over my wholly-owned works, but my business model combined with control over my content has allowed me to do this successfully for six years (modulo a very long break in the middle). And I've never charged money for anything recorded at a conference; that wouldn't feel right.
Check out my reply to andrewstuart2's post above. Seems like there is a way to make this work. Really excited and appreciative of all the comments here.