I don't understand TV commercials

I just noticed a new trend to TV commercials today because I've been watching live TV instead of using my TiVo to blow through them.

Why is it every four out of five commercials on TV feature a dumb ass, fool, or mook pushing the product or something else absurd? Where did the logic for this trend come from?

Was there actually a conversation on Madison Avenue that went like, "Hey we tried straight pitch men, smart guys and intellectuals now lets get the dumbest fool we can find to show using the product. Everyone will eat that up!" Or did they just figure out the commercial doesn't matter -- they just need to get their product mentioned and the logo on screen no matter what the context?

Not that I'm normally watching them, but it would be nice if they still tried.