A lot of people seem to be confused. Elon does not have any companies working on a hyperloop. He kicked off the idea and released a white paper with some very early engineering work seemingly put together by a group of engineers working at SpaceX and Tesla[1]. He never had any plans to commercialize it himself and was releasing it as "open source" for anyone else to take up.

Several companies sprang up to pursue the concept[2]. This article is about Richard Branson's Virgin Hyperloop which itself has a very checkered past[3] and has felt pretty scamming since the beginning, long before Branson acquired the company. Not sure if the acquisition by Branson has caused them to clean up their act or what.

The only Hyperloop thing that Elon or his companies seem to do is hold a design competition for students where they compete on a short hyperloop test track at SpaceX's Hawthorn facility. If I had to guess I'd say that this is most likely a recruiting tool for SpaceX.

1. https://www.tesla.com/sites/default/files/blog_images/hyperl...

2. https://en.wikipedia.org/wiki/Hyperloop#Hyperloop_companies

3. https://arstechnica.com/tech-policy/2016/07/former-hyperloop...