Imagine flying without ID? Not that hard to imagine.  In the US, you used to be able to.  Unused tickets used to be sold or traded.  I never led to any "terrorist attack".

The airline companies where very happy to enforce the ID check because.... it makes them more money!   In the same way: Right after the TSA started banning liquids, the airlines are starting to charge for any onboard drinks.

The age-old way of solving many problems is asking: "Who benefits?"