It's weird how many unrecognized geniuses there are in the neuroscience all claiming to have explained the brain and people just need to recognize their genius. All sounds very similar to Jeff Hawkins.
Your skepticism is warranted :) Grossberg is not that unrecognized. I'd recommend Talking Nets by Anderson and Rosenfeld and Margaret Boden's Mind as Machine. Both are scholarly histories of the field. Boden's book is far more comprehensive. Worth reading in any case if you are interested in the study of the brain and mind.