Considering that you will pay an additional fee with any cab/ride hailing service, there must be, therefore the additional economic incentive.

Airport traffic is unique. There’s no room to loiter and additional complexity in navigating. Also, there’s the expectation of luggage.

That said, airports are very different around the country and so are cultural norms. But generally, you should toss some cash or a token of appreciation to the person driving you to or from the airport.