There's a coming soon page you can check to see what's in development. It gets updated regularly:
There is a constant cycle of development in new courses.
The instructor crew do have other tasks, such as editing the Denoise podcast, one example among many other things.
However, the instructors are into the development of the next course as soon as one is released, so you can be sure there is always more on it's way fresh from the cookie ovens.