High-throughput transit isn't there to be better in 1:1 comparison with one person's car trip, but to make better cities possible.

If you only imagine this as a static scenario where everything is the same except you swap car for a train, of course car looks better.

The problem is you're not in a single-player game full of NPCs. When everyone else also chooses the car, you physically run out of space for everyone's cars, and end up with a city full of asphalt and large roads that are dangerous/inconvenient to cross and unpleasant to be around.

Car infrastructure takes a lot of space. When it can be reduced, it allows building amenities closer together, so you can have multiple useful destinations within walking distances not much worse than crossing a Walmart parking lot, and you get an environment that's nicer than a parking lot.

Being crammed in a train that moves 3 million people a day is the price to pay for not having a sea of asphalt for ~3 million cars.