Re: why do people go for online tutorials?
All very much true.
However, the good course designer starts with a particular demographic in mind as his/her target audience, and builds the course around them. A good teacher will adapt the course on the fly if students are finding it too hard or too easy.
Modern digital courseware wants to sell to as wide an audience as possible, which means all notions of prerequisite learning go out the window. Then there's the tendency for everything to be live coding instead of lectures, which means everything's paced by lines of code rather than complexity of concepts.