I see your point, but MY point is that the dumbed down factor is on a downhill grade. It boggles the mind to think the lowest common denominator could sink any deeper into the mire than it already has. But compare I Love Lucy to Survivor - night and day. For a more middle point comparison (to see the sloping), jump in between those two with a more fair comparison: I Love Lucy to Laverne and Shirley. Both sitcoms, both physical comedy, etc. I Love Lucy was hardly aimed at the LCD, but general audiences (not really the same thing). What from the past could you compare to the likes of Survivor or Fear Factor? The Gong Show? Even that was tongue-in-cheek and didn't take itself any more seriously than Get Smart did.
I still insist that fluff gets more meaningless every day. A light comedy is not the same as a comedy aimed at morons!