If he fails for making promises he could never keep, many will stand to lose. I live in the home of Toyota in Japan, and would welcome any competition that pushes Japanese automakers to achieve more, but in my opinion Tesla is not showing the signs of a business that can scale. Incidentally, I blame the American consumers, investors, media, and labor pool for that shortcoming as much or more than I would blame Musk. A great leader is still only as good as his weakest link. In my view, America is incapable of sustaining a great manufacturing culture at scale due to the influence of various perverse incentives that have woven themselves into the cultural fabric.
I don't think people are necessarily hoping he will fail, rather they believe his failure is a forgone conclusion, and they can't understand why others can't see that...including Musk.
NOTE: I'm not a hater or a fanboy.
Few want him to fail, and we'd all love the grand plans to succeed....but at some point a dose of realism has to be injected. Elon isn't a pied piper. We do need to think for ourselves occasionally, as do investors.