The Boring Company didn't fail. The boring company was a scam to delay and distract the california high-speed rail project. and it continues to delay and distract other public transit projects around the country to this day. it's been a resounding success.
Minor note: The Boring Company is a completely separate idea from the hyperloop. They instead proposed what's essentially a Personal Rapid Transit concept ("The Loop"), which has been shopped around a couple of times, but has seen no takers other than the Las Vegas Convention Center. The only public transit project it seriously competed for was one iteration of the O'Hare/Loop express transit system, but that was a zombie project that had already died a decade earlier.
The main arguments being used to militate against urban rapid transit (i.e., metro systems, regional rail; not inter-city HSR) these days tend to be "automated taxis will make all of this imminently obsolete," although that may have died down in the past several years given that a decade has passed since it was first trotted out.
https://jalopnik.com/did-musk-propose-hyperloop-to-stop-cali...