I agree with both Fred and Chris here.
Fred is absolutely correct when he mentions the 2 major problems confronting developers of tutorials: the cost and the short period of currency where the base-products are regularly updated.
Chris' comment that it is much easier to learn by example would be supported by anyone who is trying to learn a new technique.
I have been using Opus for almost 5 years, and I spend many hours each day with it. (I am retired so my time is my own.)
When I find a need to understand a new (to me

) function I usually set up a small pub to learn what to do and how best to do it. Sometimes I keep these small pubs, but mostly I discard them. It occurs to me that others might be able to make some use of these, so I am considering resurrecting those I can find.
Following from the discussion on this thread, I recently started working on a new, very basic tutorial that is planned to cover the most elementary aspects of using Opus -- and I immediately ran into a challenge that means that I cannot use the record keystrokes and mouse movements functions. Why? Because these functions only record actions that occur during a preview and only record actions that take place in the previewed editing workspace.
To provide meaningful tutorials, I need to be able to demonstrate to users how to use, and what happens with various elements in: (i) the organiser panel; the Menu Bar and associated dropdown submenus; and the tool bars and their associated submenus. As far as I can see, this requires that I set up a simulation. This is possible, but simulations take more time to develop
and thus increase the cost for any commercial developer.
Then there is the issue related to updates to Opus. Like Fred said, these can effectively reduce the useful life of a tutorial, thus increasing the price needed to be charged in a commercial operation such as that provided by DW.
I plan on continuing with my so-called tutorials to teach myself how to use all the facilities in Opus Pro XE version 4.5. Because this is a personal development there are no deadlines imposed on me, no commitment of resources, and more importantly, no need for me to recover development costs.
However, being brutally realistic, these tutorials are not refined and to date have been for my use only. To tidy them up for general release requires additional work, from which I would not benefit unless I charged for each tutorial.
I also have some doubts about how many Opus users actually want tutorials. About 12-18 months ago I publically realeased (on the forum run by John Eckker) free copies of tutorials to show end-users of Opus pubs how to work with navigation buttons and how to use the search engine. I use these all the time and include both as applications called from within other pubs.
The point I make here is this: I have no indication from any Opus developer that they found them useful. Perhaps they did, perhaps they did not. This lack of feedback doesn't matter to me because these were not commercial products, but if I were a commercial developer of tutorial products, feedback would be essential to their continued development.
So, while I can accept that a very few Opus developers feel the need for tutorials, I do not see enough interest that would make a commercial development of tutorials economically sustainable.
Just my 2 cents worth!