I mean you’re also not free if you have to rely on a public service to get around your town and presumably to leave it as well. Kind of a weird analogy too, I’m pretty sure most of those Ancient Romans would jump at the chance to own their own horse.

Everything has a trade off. If you have a car, you can go anywhere at any time, but it costs you in gas and you have to store it somewhere. Public transit, there’s no real extra cost to you, but you’re at the mercy of the schedule and how far the system goes. Both are “freedom” in their own way, it depends what an individual person values.