> Change the way shopping is done so that shoplifting doesn't work. I fill a cart, walk through the gate out the door and receive a total, passing my card/phone over a sensor to pay. Of course, this means it's on Home Depot to get it right and I'm sure there will be ways to defeat the system.

This sounds an awful lot like how the Amazon retail / grocery stores work. You arrive, scan a QR code at a gate as you walk in. You take whatever you want, and then leave without dealing with anyone. A bit later, you receive a bill in your email and a charge is made to your card.

It's seamless and super convenient. It's also super creepy once you think about how it must work. I don't think I'd go back after that one visit.