That is true that many of these things have been around for a long time. But I have not been aware of them being all put together in this specific way before GTD.
But my larger point is that in this case, its very obvious that Canfield took these specific ideas from GTD, in that specific sequence, and then just changed them a bit and called them his own, without attribution.
Of course he can do this. No one is going to sue him for it, and almost all of his readers will be totally unaware that this is what he did.
But that, in my book, discredits and calls into question his work in general. In what other instances is he doing this with other material? My gut tells me this is primarily what he is doing with most of his material, if not all of it. His work on "self-esteem" is pretty much exactly like this. Take other people's ideas, then dumb it down way too far, change it arbitrarily to avoid getting caught, and pass it off as your own, meanwhile diluting and spoiling the milk so much it can make you sick.
Even in any minor college undergrad degree, if you got busted taking other people's stuff in specific sequence, and then just changing it a bit, then you would flunk. You can't just take other peoples ideas, and just change them around slightly, and pass them off as your own. (Well you can, and many do it and get away with it, but that doesn't make it right. I could list person after person who has done this). All he needs is a small footnote that points to the source material. But perhaps if he did this, then there would be nothing left.
I just don't respect people who just steal (yes steal) others ideas in any field, change the words a bit, and pass it off as their own. I find that very sleazy, and intellectually dishonest. And I don't like this type of dishonest behavior, especially when it comes from professional salespeople or writers, and I will call them on this every time.
If this guy operated in any type of proper intellectual arena, he would be totally massacred and discredited for doing this type of thing, and deservedly so, in my view.
So my point is a more general point, about this type of intellectual dishonesty, in all contexts.
My other point is that this is why I get my milk right from the horses mouth, whenever possible. I avoid copies of copies of copies, because the further you move away from the original source, I find in general the more diluted and sour the milk gets, until it becomes rancid and can make you sick.
There are countless examples of this, the most egregious in my view being in the pop-psyche paperback wasteland.
There could be an entire book or documentary made about this subject.
Maybe I'll see if someone has written a book on this, and then OCR scan the book, and use "find and replace" and change the words around, and then call it my own and sell it! Cool...