Okay, then let's remember this the next time something does happen on a plane (shoe, panty, molar bomber, whatever) and then again remind ourselves of this just before TSA and DHS ramp up security and do stupid things like say you can't have anything in your lap during your flight or you can't go to the lavatory during the last 60 minutes of your flight.

Everything involves risk, including flying.

Per your statement, let's stop pretending we can achieve perfection. Let's just tell people that the government/TSA/airlines will do X, Y, and Z, but it is a waste of time, effort and money to do any more (honestly, waving chemical strips over drinks purchased airside?).

If people show up at the airport, they have made their decision to take the risk of imperfection in securing the plane and everyone can call it a day.

I, for one, am more than happy to take the risk we had on 9/10/01 even knowing what we know today. I was much happier back then as a passenger and I am pretty sure that - give or take some minutia percentage - I am probably just as safe and the risk no better or worse.