[DuskStar]

If a Boring company tunnel has 1/10th the capacity of a subway but costs 100 times less, that's a major win. Parallelism is a thing here, after all. (hell, if it has 1/100th the capacity at 1/100th the cost that's still a major win, because it lets you build incrementally and following a wider variety of routes)

[gamblor956]

The problem is that the boringco tunnel at max capacity has roughly 1/100 the capacity of a subway but only about 1/10 the cost. Scaled up to equal volumes, it would actually cost 10x of what a subway costs.

The expensive part of subway construction isn't the tunneling, and hasn't been for decades. The expensive part is constructing the subway stations; each station can itself coast as much as all of the tunneling.

BoringCo does nothing to solve this. It addresses the most cost efficient part of the problem that, even if they can introduce efficiencies, would only cut a fraction of a percent off the cost of public transportation systems.