> I was worried this was going to be some pie-in-the-sky idea

Sure, they put a lot of theoretical analysis into it, but its still pretty pie-in-the-sky. From the last page, note that

  The authors recognize the need for additional work,   
  including but not limited to:
    1. More expansion on the control mechanism for 
       Hyperloop capsules, including attitude thruster or 
       control moment gyros.
    2. Detailed station designs with loading and unloading 
       of both passenger and passenger plus vehicle 
       versions of the Hyperloop capsules.
    3. Trades comparing the costs and benefits of 
       Hyperloop with more conventional magnetic 
       levitation systems.
    4. Sub-scale testing based on a further optimized  
       design to demonstrate the physics of Hyperloop.

It's not a current competitor to high-speed rail, its more in the position that high-speed rail was in in the 1930s.