Y'all must frequent different airports than I do. It's rare that a shuttle driver gets up out of the driver's seat to offer me assistance. So rare, that I would usually have my luggage (one small carry-on) at least in hand, if not already on the bus well before the driver arrived to assist.

OTOH, if it is the rare occasion that I have a heavy suitcase or two, I greatly appreciate any assistance offered, and I tip accordingly.