Still, major airports all want you to arrive quite a long time before your flight's scheduled departure.

Not much point in spending $$$$ on fuel to knock an hour off a 4-hour flight, if I end up with an hour-long wait at each end.

Except that sometimes the Precheck line is longer than the regular line. Has happened to me a number of times. I still stay in the precheck line because I don't want to take off my shoes, but as precheck becomes more popular, the speed advantages decrease.