I would imagine that revenue for this sort of product would be hard. It's new for WordPress, but we have had software and technology to do with already for at least the last 14 years.. With sites like http://www.videousermanuals.com that already cover WordPress and creating training tutorials.. If you know where to look, you can even get software to do it for free.

https://wordpress.org/plugins/tags/tutorials
http://www.woothemes.com/products/sensei/
http://wp101plugin.com
https://premium.wpmudev.org/project/unbranded-video-tutorials/