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This nicely sums up how the "non technical" musk afficionados think.
Guy has a genius idea and the money and charisma to successfully market it against the then odds of resource availability and cultural resistance to change (tesla) and automatically they think everything he shits is gold, no further scrutiny necessary.
Spacex is not a new idea, neither is it cheaper than other rocket systems, same goes for his tunnelling projects. With spacex he filled a hole left by NASA, though. "hyperloop" (he did not mention) is not a good idea when you really start looking at it in (not even that much detail required).
It is also a nice example how you can be an expert in one field (for example psychology) and have not even a remote understanding about another (for example engineering).