Why don't we have drive-thru post offices in the US?

We have drive-thru banks and fast food?

Yes, of course there are the drive-up mailboxes for dropping off letters, but that’s not what I mean. I’m talking about a window with a human being, where I could give them a package, have them weight it, print the postage, and send it on. Or maybe I would buy a roll of stamps, or whatever else.

Sure, put a limit on it—three transactions per person—but it would be a big convenience.