Earlier quoted context omitted.
Proven what? His main claim of glory, Tesla, still hasn't achieved what he built the company for: making EVs mainstream. Rather than the ecological revolution he pretends it to be (his focus on climate change), it is still nothing but an expensive toy for the wealthy. Not exactly selling at the levels where we could talk about making a change for the planet. Maybe you're referring to SpaceX in proving skeptics wrong?…
I think this crazy tunnel thing Elon just announced looks horrible, but the moment you claim that Tesla and SpaceX aren't doing anything special is where it becomes pretty obvious that you don't know what you're talking about.
Not saying it isn't possible or what he has achieved isn't great. Just saying his existing successes don't prove what he's proposing will succeed, since, his new goals are as big or bigger than his initial as-yet-incomplete goals.