This is downtown Seattle to SeaTac I'm talking about, in case anybody wants to dispute this. Your starting point and destination can both be right on top of train-stations and cars still beat it easily because cars don't stop at a dozen train stations in between.
This said, I still use the light rail when I'm not in a hurry because it's pleasant. But there is absolutely a convenience price to pay with mass transit. Going anywhere takes longer in almost all circumstances, even when you account for traffic slowing cars down.
Also this is what railway lines looked liked in the US when we cared to build out our train infrastructure: https://i.pinimg.com/originals/3c/57/ee/3c57eeffb7e1a3c78691.... Just because the US is big doesn’t mean we can’t build tracks.
The reason this won't happen is the USA just can't build major public infrastructure anymore.
Europe, the East ... even parts of the developing world have surpassed them in this regard.