Many journalists and social media experts are surprised that Elon Musk would go into a business that he doesn't understand and refuse to listen to anyone who does. But we who work in urban transport planning already knew this about him. https://humantransit.org/2018/12/elon-musks-tunnel-it-doesnt-scale-so-it-doesnt-matter.html
Elon Musk's Tunnel: It Doesn't Scale, so it Doesn't Matter — Human Transit

Elon Musk just gave the media a tour of his 1.5 mile prototype tunnel under Los Angeles, which he spent US$10m to build.  Why are Elon Musk’s tunnels so cheap?  Because they’re tiny. As media photos of the event will show you, the tunnel is just slightly wider than a car.  That means that if […]

Human Transit
@humantransit its also not surprising to anyone knows that his greatest contribution to paypal was demanding they move their entire backend to windows server, a thing that is not just literally impossible but also provides no benefits whatsoever for an absolutely ridiculous amount of work, and he had to had keys jangled in front of him for an extended period of time to get him to drop the decree