No prototype - nothing even remotely close to a prototype. At least rockets and electric cars had some basis in reality before Elon started working on them.
Those two statements are however false. As is calling the hyperloop a train. If it was a (fast) train, Musk likely would not have called it a fifth mode of transportation.
This isn't like any other high speed train in existence. The rail cars have more in common with a vtol jet than the train you linked.
What leads you to believe that Musk is incapable of building an entirely new technology?
I believe Musk is perfectly capable - just as Dean Kamen is a capable, successful inventor.