I am fairly familiar with the local bus network in Orlando Fl. As a passenger, for a bus service, it's pretty good. Inexpensive and most routes are frequent enough, although some are just hourly and a tiny number are less frequent. It's integrated (since there is only one operator - the city) and inexpensive to use - $2 flat fare one way, with transfers to other routes inside of 90 minutes at no extra cost; all day $4.50; weekly $16. etc. Half fare for children and concessions. It has a clean modern fleet. Buses all have bike carriers.
It is obviously subsidised. One thing that does set the US "system" apart from ours is that they can, and do, raise taxes (on sales of merchandise, restaurants, etc.) at local level and determine locally what to spend it on. I don't know what the numbers are, but they could (and do), say, add 0.5% sales tax for transport; decision made and impemented by the city.
I suspect the political motivation is to keep the low-paid moving, but, of course, services are available to anyone. Sure - anyone with use of a car will probably use that, but as a visitor, I have saved a fortune (at the expense of some travelling time) on car rental and insurance. Two weeks trip, two weeks travel anywhere in the system for $32 each.
In fact - I see that network with a degree of envy, when I compare it to the machinations of First (and, to a lesser degree, Stagecoach) hereabouts, with, between them and the PTE, a totally bewildering plethora of tickets of varying coverage and provider and price and no practical integration (beyond premium priced multi-mode passes).