People don't remember just how good it used to be. I used to lock my luggage securely, carry a knife on my person, and walk with my friends/family to the gate. Nobody asked pointless yes/no questions about the history of my luggage. When the airport wasn't busy, they might not bother to have the security station open at all, and just waved everyone through. A couple times, we drove to the airport an hour or two before the flight and bought tickets at the check-in counter (it was a very early flight that was never full), and this didn't arouse any suspicion. You didn't need to get out government ID for anything, since tickets weren't locked to the purchaser.

"TSA pre-check" sounds like it eliminates one inconvenience of flying in the USA in 2018, but not the other 34. I can't imagine what it might take to make me want to get on an airplane again.

Until everyone does it. I've seen the pre-check line longer than the normal line.

The pre-check line doesn't involve all of the slow-downs the regular line does. I've seen it longer too but it easily moves 10x as many people through.

Nothing needs to be removed except metal in your pockets, you typically walk quickly through a metal detector instead of the slow body scanner, and while they probably shouldn't, bags don't seem to get looked at as thoroughly either, so no delays while your backpack gets sent through twice and then pulled off to the side to be inspected.

Pre-check-level security can move more people through faster, though, so if everyone does it, it will still reduce overall/average wasted time.