Choosing not to own a car creates its own demands (on your time, your comfort, your freedom).
Anecdote: my brother-inlaw lives in Chicago (one of the places in the US where not owning a car is quite practical), and purchased a car. Why? Because he attempted to do a home renovation himself over the course of a winter without one. Hauling around tools, materials, and himself on a bike in snow and slush was not something he ever wanted to repeat.
Even something simple like grocery shopping is a pain without a car. And delivery services (someone else’s car) or a nearly daily shopping trip are the only alternatives.
Plus, Chicago is a place where it’s far easier to be car free if you’re wealthy. The north side is where most of the density is, and the highest real estate prices.
I judge Chicago (minus the extensive suburbs) as more of a one car per family situation. Which is better than most of America but not car free.
"Requires a down payment, finance payments, registration and taxes, dmv lines, insurance, maintenance . . ."
Does life not involve responsibilities? How does this imply OWNERSHIP over oneself? Tally that actual amount of time all of these responsibilities actually involve rather than assume that the rest of us are overwhelmed by your exhaustive list.
It didn't take long before you had to stretch to find these nearly insurmountable obstacles.
"Now you need a better job and probably stuck in traffic more often in service of the car."
Did you stop to consider that this better job that wasn't available without a car might be a reason why you also have a higher standard of living and more liberty to spend your newly acquired free time doing what you enjoy?
"No wonder rideshare and rentals are taking over"
Ever heard of buses, trains, and taxis? It isn't like these things never existed as options that people -- including car owners like yourself -- have used before.
"I have a very old car. . ."
So does it OWN you? The point of contention here is ownership. Before the car, people may have owned horses. Owning a horse involved a lot of responsibilities as well, but it also provided a service for people. That doesn't imply that the horse owned the owner.
It’s an expression to warn a young person about the reality of car ownership, that you become a slave to it. It requires a certain amount of imagination. Cars are not a barrier to good jobs, one simply moves to where the commute is acceptable.