Well, what should the government do then? You are saying that the screenings don't mitigate the risks, so then what should be done to mitigate the risks?
This has been asked and answered in many forums and news programs. No one wants to hear it, but by all accounts it's effective.
Simply adopt a system similar to that used by Israel. They use info from your passport, interviews, intelligence and (probably) gut feel. You could call it profiling, but that's a loaded word. I would call it "screening". If you Google it, you could find some details. The idea is that you screen the people instead of the stuff they bring onto the plane. (How will we ever screen for internal devices - give everyone a cavity search
?)
TSA types say the USA is too big to do Israeli style screening. What a cop-out response. No, we couldn't start doing it tomorrow, but we could eventually - and we probably will if there is another significant, successful attack which can't be caught by our current "new and improved" methods. Are there "issues" with such tactics. In a word "yes". But the Israeli system has been very effective and is carried out in the most likely target in the world. I wouldn't say we've been very successful by the various methods we've evolved over the years (think, 9-11).
Another good thing about the Israeli "system" is that it can be modified very quickly. Scanning machines and pat-downs are a one-size-fits-all approach that probably work for many threats, but not for ones we haven't seen yet. (Again, think cavity devices). Once these methods fail, there's no easy fix - okay, I guess strip searches and cavity exams, but, sheeeesh!