That's assuming there's only one tunnel. As the article mentions the point is to dramatically reduce the cost to bore tunnels, so you can bore more of them.
If you could bore 4x the tunnels, you'd need a capacity of 4 people per car to match peak BART. And... hey, that describes pretty much every car in existence. But using the BART comparison: recent estimates [1] put each additional mile of BART track at over $1 billion. So if it really costs $10MM/mile for the Boring Co, you could bore 32x the tunnels and beat BART capacity by a factor of two assuming even single occupancy vehicles, at about a third of the cost.
If you could bore 4x the tunnels, you'd need a capacity of 4 people per car to match peak BART. And... hey, that describes pretty much every car in existence. But using the BART comparison: recent estimates [1] put each additional mile of BART track at over $1 billion. So if it really costs $10MM/mile for the Boring Co, you could bore 32x the tunnels and beat BART capacity by a factor of two assuming even single occupancy vehicles, at about a third of the cost.
[1]: https://sf.curbed.com/2018/6/18/17464616/bay-area-subway-tra...