Trains and buses in the US, where they exist, have ticket prices on par with the amount of gas a single person would use driving a used car. For very long trips they're a bit cheaper (up to 2x). For very short trips they're often a lot more expensive (up to 5x). For trips more than an hour or two, the one-way cost usually has no significant discount on a round-trip ticket, and you can pay 10x more if you don't buy well in advance and go on the cheapest days.

The effects of that vary. Relating to TFA, if you were making this trip 6x per year, could plan the dates, were always travelling alone, and didn't need any transportation anywhere the rest of the year beyond what walking and biking could provide, you'd expect the train to be about break-even with gas+maintenance. It wouldn't be worth having the car.

As soon as any of those assumptions change though, that logic goes out the window.

Suppose you have to get to work (and that rent/housing is enough higher near work that it's worth commuting _somehow_ by a substantial margin). The markup for short trips is very high for public transit, Uber, and all your other normal alternatives. You'll be money ahead on a decent used car (clean, no body damage, new enough to easily last 100k miles even if you know nothing about cars) in a year, even counting the entire purchase price, taxes, insurance, and everything else.

Under the assumption you have a car already and only have to consider unit costs (depreciation, gas, maintenance), trips like TFA can start to make a lot of sense to drive, depending on your personal preferences. Every long bus trip I've taken in the US has been so rattly and bumpy that I couldn't sleep or type anyway, and by the end of a trip they've been so full that I couldn't type anyway (tall, broad shoulders, the geometry doesn't work out in narrow seats with so little space to the seat in front of me that I already have to angle my legs just to fit). I'd much rather listen to my own music or a cooking show or something, keep the temperature exactly where I'd like it, have the flexibility to carry a few extra items, and get to my destination in half the time without stopping 20 places to pick up more passengers. When the money's a wash, I'll pick the car every time.

If you're willing to make tweaks to your life to save money/fuel/..., it's also worth looking at the possibility of carpooling. If you can go with one other coworker, you're already a lot of money ahead on the train. If you additionally didn't know your return date in advance (variable length job, which you're staying at for a small but undetermined number of days), the difference in ticket prices would be enough to completely pay for insurance and taxes for the year, on top of depreciation, gas, and maintenance. Those 6 trips would justify owning a used car for any other part of your life where the unit economics made sense.

If you work remotely, live in a nice climate close to groceries, or have any number of other nice properties to your life, a car doesn't necessarily make sense. Our infrastructure doesn't often make the alternatives pleasant though. E.g., I was pretty adamant about biking through college. The city wouldn't plow the bike paths till days after any major snowstorm though, the snow was always falling into the edges of the road, and there was a zero percent chance I was going to bike out in the middle of an icy 45mph road in front of pickup trucks who think it's sane to tailgate in those conditions. 6+ months each year, the only non-car option was walking. I did that a couple winters, but 5 miles each way is a bear when you're trudging through snow, and the one semester I had an evening class I always thought long and hard about whether I'd stay at school an extra 8 hours or add an extra 10 miles to my day.

Details vary, but _most_ Americans are in some sort of similar situation where cars are the only realistic option if you can possibly afford it. Trudging through the snow when it's <-10F the entire month of January is fine if you're young and single, but I wouldn't want to carry a kid to their doctor in that environment. Tons of people just live too far from town for non-car options to be practical. Roads poorly designed for rain and pedestrians limit the safety and practicality of biking in other huge swathes of the country. And so on.

Mind you, I'm not against public transport or anything. The BART trains here in the Bay are something I use a few times a year, and they're perfectly fine. You can even get work done on them if you'd like. My point is that cases where trains and buses are the best option (or even any option) are so rare that for most Americans you can assume that the cost of insurance and taxes for a car have already been taken care of, so that only the unit economics of a given trip play into whether you'd drive or not (when considering it financially).