Honestly, I think it’s more convenience than cost at the current price point. From most areas of the city it really is far faster to take a cab or even an airport shuttle from midtown than navigate the subway with luggage. It’s not an easy transfer if you are carrying multiple checked bags, and if you’re traveling for business, your company is probably paying for the cab anyway.

If there were multiple points in the city where you could essentially get an express option to the air train and there was an easy transfer between - you’d have a lot more people using it.