The consensus seems to be that pop culture is getting dumber and shallower with every passing decade.

I agree. Here's why:

Think of the collective pop culture subconscious as an expanding sphere. Following 4πr³/3 and 4πr², the volume of said sphere will always grow faster than its surface area. We are the volume, the surface area is our collective knowledge (of the universe and ourselves).

As you've probably seen, we are running out of room.

The problem with our generation is that the human memeosphere is on a collision course with its own finit--y? finiteness? finitude? (ah screw it, you know what I mean). The human animal is limited, the human race is limited and we all like sex a lot ... hence all the repetition, imitation, mashing-up, remaking, remixing, homaging and so forth. If we don't find something new to say or think or believe, pretty soon we won't even need to be intelligent or inventive anymore. Life by rote, on an infinite tape loop.