I certainly agree that passengers consistenly fail to pay attention to briefings(having experienced everything from loud talkers, those who out-right refuse to pay attention and those who would even lie to crew about having read the card at type III exits!).
But with exception of the humour used by a few carriers, how often do you see a safety demo or video that can really capture passenger attention well? If we saw the same ad on TV 50 times, I'm sure most of us would begin to tune out... in some regards the safety demo is no different (at least in the eyes of passengers).
Perhaps the development of safety briefings isn't getting the attention it deserves?