I would argue we are still in an era of cheap gas. Expensive gas is more like $5 - $7 in the midwest. I'm sure out on the coasts you're pumping up against that already. You're idling for maybe 10 - 15 minutes, so most people don't care.

In my experience a drive through is a dine-out experience. It's not so much we're eating in our car and not stopping, but I'm going to go get fast food to go.