Just because something is being built with other people's money does not make something a success. None of the companies Elon has been involved with have ever actually generated a profit -- they have largely just taken advantage of speculative investors and their willingness to buy into his ideas.
"Just because something is being built with other people's money does not make something a success."
It doesn't preclude it, either.
Pretty much every business larger than one or two person operations uses Other People's Money to grow to profitability. See Facebook, etc.
Use of OPM doesn't guarantee success, but for industries that have large capital entry and operating costs, it's necessary.
Musk is working in fields that manipulate matter, not just bits - so it will take longer to see if Tesla and SpaceX reach profitability ("success") than it would for a generic software startup.
Be patient. You may not know whether a company or a child is successful for a couple of decades, at least.
* gigafactory under construction
* freemont factory producing ~50K vehicles/year
* spacex successfully, repeatedly delivering payloads to orbit (and successfully demonstrating their crew escape vehicle recently)