Calling it scam is rather disengenious. Especially if you consider that nearly the whole 3.5 books were available for free online.Snip.
We played dnd for quite a while with 3.5 rules without buying a single book.
Also 4e books were not worth the paper they were printed on, as the rules have been updated so much, i bet not a single power could be used straight out of the book. Also here too you could see a shift bqck to traditional dnd which paved the way for 5e, even thoigh there was nearly no target audience for 4e essentials, because most people either loved 4e so much that they did not like the changes or hated it so much that they didn't even consider 4e essentials.