It’s not your imagination. The Audacious Epigone explains:
The mean IQ scores, converted from GSS wordsum results, assuming a national average of 98 and a standard deviation of 15, of those who attended college for at least four years by the decade they graduated in* (n = 5,124, though n for 2010s is only 49 and should be seen as merely suggestive–the trend is clear regardless):
The change in the intelligence of the average college graduate over the last fifty years approaches the IQ gap separating whites and blacks.
College for everyone has been an unmitigated intellectual, academic, cultural, and economic disaster.