> The point is, building tunnels underground for personal transport vehicles as a "solution" to traffic is a terrible idea, and something only a showman can sell.
The fundamental point of boring company is to reduce the cost of underground boring. Shoving cars through tunnels is a means to an end of reducing the cost of underground boring. It's about finding a path to make some kind, any kind, of money off of boring in order to make the product development costs self-feeding. This is why the idea of cars driving through the tunnels was done rather than the original idea of putting cars on platforms through the tunnels. Cheaper and faster to market.
Musk started boring company with the idea that transportation needs to be 3 dimensional, and not just adding another single layer of transport under the ground (trains/subways), but having a whole ton of layers going deeper and deeper into the ground. Now they've done their first iteration of tunnel, which is quite bad, rinse and repeat until it gets cheaper.
BTW, Musk has never come out against subways, his point was just that in the US, people drive into cities in cars, so if they're using cars, then the transport system in the city needs to handle cars in a three dimensional way.