He didn't need to finish it in order for it to have an impact. Makers of FilePilot and Animal Well both attribute Handmade as being big inspirations for them to go the way they did. They said, they got the most value from the first 50 eps or so. You'll hear lots of them on the Wookash podcast.

If you mean Computer, Enhance!'s Performance Aware Programming series, it's ongoing, but the pace is slower than about 1.5years ago. Given how good it is, and how fastidious and comprehensive Casey is, I imagine it doesn't really pay for itself, even with an impressive subscriber count.