> The Boring Company's main plans, as can be evidenced by their communications (such as their FAQ) and their commitments and attempted commitments to build actual projects
Agree that this evidences their short-term plans (1-5 years), but I actually think it's a poor-proxy of evidence of their long-term (5+ years) plans.
I mostly agree with you about their short-term plans, but my understanding (which could be wrong!) was that they had longer-term plans, of which the proposed tunnels are stepping-stones and learning opportunities towards.
Though, I'll readily acknowledge that the evidence I have for their long-term plans is thin (mostly some interviews with Elon Musk about The Boring Company, and having seen similar developments at SpaceX), so if the counter-argument is that the long-term plans aren't well-enough evidenced to be worth considering, I wouldn't disagree.
I also think it's totally reasonable to argue that those long-term plans aren't realistic or a likely potential outcome.
> Oh, and for good measure, tunnels are not why subways are expensive. It's station caverns and ancillary infrastructure (such as procuring more rolling stock for the extension) that consumes most of the cost of a subway, so it's not clear that cheaper tunneling would actually meaningfully reduce the cost of building new subways.
I don't know that I agree with this. Tunneling is definitely a significant cost whenever it happens under a city. For example, the SR99 tunneling project in Seattle cost ~$2.1B dollars to build (https://www.wsdot.wa.gov/Projects/Viaduct/Budget), and that doesn't involve any station caverns or rolling stock. It does, obviously, involve the highway finishings and road connections, but tunneling is a significant expense whenever it is required.