I don't think many people would argue that there is a need for airport security.That need is as much for safety (preventing some goose from walking onto the tarmac when aircraft and other equipment is operating) to something more sinister.
However,most airports are owned and run as a business and as such the main criteria is the dollar.The owner of SYD is a case in point when you need to take a loan out to buy a meal and a cup of coffee.
That also means that they are going to put the blowtorch to security and accept the cheapest tender that accepts their requirements.As socks and thongs said how can you get adequate anything when you pay them $10 per hour.
Darth has said that he does not like paying for air marshalls simply because they cost money.I have always had the impression that he must hate putting his hand onto his wallet for anything.I wonder if he eats Kosher meals!!!
So at the end of the day it comes down to the cost and with anything you get what you pay for.