I started in 2013 to have a yearly trip to Miami for a cruise at the beginning of February. For a solo traveler, taxi had been rather expensive unless you managed to pool with someone right at the airport, so I was glad to find the shuttle operators sitting next to the taxis right at the curb, and I could just walk there and get a ride. Nice low barrier to entry. Especially after realizing that indeed, public transport of the kind typically found at international airports in most other countries (trains, buses) was almost non-existent there.
While I clearly see how Uber and Lyft can provide an identical or better service (because of less drop-off stops) I still think the higher barrier to entry of a) having to know about them and b) having to download an app and open an account is a significant downside, especially for foreigners who haven't been in the US yet. It's another slightly weird thing that you have to know about and prepare for in advance.
I have been the foreigner using an unfamiliar terminal. Since it was a cruise to Vancouver, my cruise travel agent recommended I use a cruise message board for that city. I thereby got info on the whole range of options. Plus of course we could have used the cruise line's transfer (i.e. big ole bus) from cruise ship to airport. We hired a car and got a description from the driver of the places we passed through. Thus I learned to use such message boards as a starting point. Plus I learned to have contacts.
While I clearly see how Uber and Lyft can provide an identical or better service (because of less drop-off stops) I still think the higher barrier to entry of a) having to know about them and b) having to download an app and open an account is a significant downside, especially for foreigners who haven't been in the US yet. It's another slightly weird thing that you have to know about and prepare for in advance.