And I agree with Dr. Bob and Professor Krashen and Karl Wheatly. I taught high school English for 37 years, and paid attention to my sophisticated readers--who all had excellent vocabularies. They were all, without exception, avid readers. And, by the way, they hated with a passion vocabulary drill. They thought it was boring, tedious, useless.
I would love for Mr. Hirsch and Ms. Sparks to find me one student--just one!--who didn't like to read and read rarely, and yet had an excellent vocabulary acquired through drill.
Pulling kids through endless vocabulary exercises does nothing to develop them as avid readers. Au contraire.