I think the main reason this process may not work for some people is the inability to change the way they assimilate information.
Or in another word - stubborness. The world is packed with stubborness. People just don't want to change.
As a beginner I can't claim vast reading improvement speeds however there are fundamental points raised in the book that are intrinsically important in understanding how we learn. The part of book relating to how children learn has had a profound effect on my life. The peripheal vision part also - this is also a technique encouraged by practitioners who help myopic people (people that wear glasses for distance) improve their eyesight.
Even if this book had nothing to do with reading, it would be grandly informative and enlighting.
One thing I noticed right away (that doubled or quadrupled my reading / scanning speed) was the point of actually asking yourself what do you want to learn. Once scanning quickly in a blurred out state, my reading speed easily doubled. And I don't necessarily mean scanning many pages ahead. It could be just a few paragraphs. For some reason the words were more familiar and I could pass paragraphs quickly that didn't have relevance to my quest. At first I thought I was just skimming, but it has been proven to me over and over again. This is invaluable for people scanning publications (mags, etc) for information pertinant to their own personal situation. Invaluable for the internet which could be called the center of irrelevance.
This is a core fundamental process of data assimilation - that needs constant practice and much patience. There are several techniques that need to be mastered before you can "flip pages once a second".
But the important thing is "Will it improve your reading". OF COURSE IT WILL!!!
Keep your mind open to new ideas. Try them!
Don't expect a miracle instantaneously. Expect improvement instantaneaously.
And over and over and over.......... 
And finally, watch how kids learn. This is, for me, the most important point of the whole book. This is the real key to voluminous information assimilation.
ps - Are you using PhotoReading to read this?
