I have TSA-precheck and still generally arrive 2 hrs before departure regardless of which airport I am using. Pre-check only saves you time going through security, all of the other things that take time at an airport will still apply. There could be traffic or weather delays when driving to the airport. You still need to park your car and get to the terminal. At any airport you just never know how congested it will be and if checking luggage, you have to wait along with everyone else. Depending on your departure gate, you might also have to walk a long way. Precheck doesn't eliminate any of those.
I would rather be early and have time for a coffee/snack or to shop then miss my plane. I don't consider it a waste of time to arrive early, but good planning when traveling by air regardless of where you are going. The flight will leave without you if you aren't at the gate on time. Cutting it too close and hoping to get rebooked on a future flight is not my idea of how to plan for travel.