The TSA has been proven many times over to be totally ineffectual security theater - theres this popular report from a few years back that the TSA has a 95% failure rate when their measures are tested[1].

It doesn't go anywhere because there is now a lot of private industry in it for contract money to supply the spectacle whom have the lobbying power to keep it in place, but it is a total waste of money and gross violation of privacy for no positive benefit to society.

[1] https://www.huffpost.com/entry/tsa-fails-95-percent-tests-ho...

Ok, I misspoke : the US introduced less effective security measures than other countries had before.

In particular you'll see other countries focus on measures like interviewing (briefly) the passengers as they board.