It can do that because its riders are forced into miserably packed standing room.
Private vehicle transport can also be much denser if we give up such requirements as "sitting" and "personal space." You could pack, like, 20 people into a Camry and it'd still be far more pleasant than BART between 5-10am or 4-9pm. Of course, some of them would be in the trunk and others tied to the roof rack.
Yes it does! I UberPool to work quite a bit, and have not poofed out of existence by participating in a geometric contradiction. You are claiming that we should ban something that currently works; "it doesn't work" is nonsensical as a supporting argument.
>people happily stand in public transit for the dozens of minutes they have to spend there, and have satisfied with their experience.
In many places, people happily go without basic medical care, electricity, or indoor plumbing. All of these things are terribly expensive and somewhat environmentally damaging, people who lack them are still happy, so... let's ban electricity?