Anything they do happen to build is incidental to that goal, and as such it's unsurprising that actual construction would be a shitshow.
It would be cool if they'd post a postmortem or something, but I get the impression that reporting bad news is a good way to get fired in an Elon-run organization.
Anyone claiming they can 10x the speed of a physical process that has been worked on by thousands of engineers over more than a century is full of shit. Anyone who bought that explanation is either far too credulous or just doesn’t understand what it takes to bore a large diameter tunnel.
Metal machining processes had been around for well over 100 years when tungsten carbide tooling came along, and that increased cutting speeds by 10x over HSS. It happens.
It’s a complex process with work crews, management layers, multiple subcontractors, multiple stakeholders, etc. Replacing the tool on a CNC mill with a tungsten carbide tool takes what, a few minutes? Assuming you already have the tool.
It’s also insanely easy to verify a tungsten carbide CNC tool is 10x faster at cutting metal than high speed steel vs. testing ‘This tunnel boring machine will be 10x faster.’
One takes minutes, the other takes years.
What technology or research was the Boring company sitting on that it expected to utilize to get this advantage?
Lithium batteries were "coming soon" for like 30yr.
Lithium batteries at all points were quite specific "we think <process> will reduce costs and make them viable".
Space travel is also far less mature than tunnel boring technology, I’d expect advances in space travel before tunnel boring because there’s low hanging fruit. Space travel used to be done only by nation-states, only in the last 25-30 years has private space travel been possible. Tunnel boring machines were invented 200 years ago and were useful about 150 years ago.
The costs of surveys, hvac, seismic research and maintenance required to keep a deep-underground tunnel going are much higher than cut-and-cover. So, even if tunnel boring was free, it still wouldn't make sense to prefer it over other options. There are very scenarios where deep-tunneling makes sense (dense cities, across rivers when bridges are infeasible), but they're the minority.
In most transit projects, cut-and-over is blocked not because it's a bad technical option. It's because NIMBYs refuse to permit on-the-ground disruptions or noise of any type. San Jose is the canonical example. It's a political problem, not a technical one.
Well that was the purpose of the Hyperloop too
The original proposal was squarely aimed at disrupting CAHSR, but existing bureaucratic dysfunction is more than sufficient to prevent anything being built at that scale in the US, so Hyperloop was proven unnecessary and abandoned.