I rarely see the millimeter scanner at less than max throughput.
That said I regularly do what I can to slow things down, and sometimes take the pat down in favor of hassling the staff.
Attrition is damned right. The TSA scam is awful, and I hope we can get rid of it soon.
If that's true, then some other things fit neatly into place. The airline escalation of baggage check fees has driven people to carrying more stuff. That, in turn, means that more stuff needs to go through the x-ray conveyor, which slows down that process.
Stealing stuff right out of the security checkpoint ought to make those folks think twice, right?
With cameras, laptops, and other expensive items, I have to carry on at least one bag regardless. Now, it's one or two bags (roller luggage, plus laptop case, usually).