Interesting.

As far as I can tell, they're at least supposed to use location services to start the order when you're nearby. When the store isn't super busy my order is typically ready when I arrive, and I've ordered 10-15 minutes before arrival a few times and my orders weren't cold.

Maybe this is what they're supposed to do, but the system and/or employees don't do it reliably.

Or perhaps it's because I typically do counter pick-up, and almost always have a small (1-3 item) order.

It makes sense that they wouldn't prep your order if you're just going to be waiting in a long drive thru line anyway, though this could obviously lead to further delays because they don't reliably have larger orders finished in the time it takes to get from the speaker to the pick up window.