It's amazing to me the amount of negativity directed toward his projects and the millions of reasons people give for why they "won't work" (not necessarily on HN, but at least on general news websites). I'm starting to believe the only difference between those who start their own companies and those who don't is that the latter convinces themselves that it is impossible, never builds anything, and from their own lack…
It's possible to start your own company and still think Musk's ideas are foolish. People are giving millions of reasons why they won't work not because they are haters, but because there are millions of reasons why they won't work.
With Musk's established track record I think it's pretty arrogant for anyone to call his ideas foolish. He has achieved things that people thought were impossible or bound to fail. You can say: “I can see this potential problem”, or “I wonder how he's going to deal with this physical limitation” or similar sorts of statements. That's feedback and analysis given with respect. Simple dismissive negativity against ideas put forward by a person who would already rank in the top 10 in the world today for technological and engineering achievement is arrogance and narrow-mindedness.