To suggest that basic literacy and educational attainment are somehow indicative of above average intelligence or the ability to understand complex and abstract ideas is a bit of a stretch.
With grade inflation and babysitting modern age students, what are the realistic requirements to attain a university degree in a low-difficulty major at a mediocre school? 80 IQ? 85?
The literacy argument is trivially refuted in a similar manner. Reading by itself is not indicative of higher cognitive function above an elementary school child.
Also, proportions are what matter here. I doubt the proportion of people with high fluid/crystallized intelligence is higher now, than it was, say in 1850. The only difference is that now a higher proportion of the general population have degrees.
