More important, they are published for people who are passionate about abstract ideas, and find it invigorating, thrilling, and exciting to see them batted about. This is not the profile of the general mass reader
I wonder if this is not also pertinent to the issue of concentration of reading. 50% of the adult population in the US and Europe read no discretionary books in a year. 10% of the population would appear to be responsible for roughly 80% of books magazines, etc. that are read. I strongly suspect that this is in part culturally driven; were you raised in a reading culture? But I wonder if Podhoretz's observation isn't also operative, i.e. are the minority of intense reader's those that are also invigorated by ideas?