The author's point was that college IQ was dropping, and this explained the lack of rise of CS enrolemt. Simce CS is objectively harder, only a lower portion of

The author's point was that college IQ was dropping, and this explained the lack of rise of CS enrolemt. Simce CS is objectively harder, only a lower portion of college students can now do it. That's their hypothesis. So their hypothesis isn't that CS student IQs are dropping.