The thing people don't seem to be realizing is that he's setting up a lot of his investments into colonizing Mars. He has electric cars, to drive on Mars. He has battery tech, to store energy on Mars. He has solar energy tech, to produce energy on Mars. He has the Boring Company, to build tunnels on Mars to shield from radiation. He's now building robots to assist with jobs (on Mars) that humans might not be able to do... Getting the picture yet? If you think Tesla and Elon's focus is on Earth, you are missing the big picture. He's basically going to control all usable land and colonization of Mars. I imagine that will be a profitable venture for him. Nobody else is even close...
your getting there but your still only seeing half the picture..
to other readers
elons vision is not to own a car company or a solar power company
think of his ventures as just R&D of a bigger project. and then piece it all together it start to make sense
he didnt start the 'boring' company to make transport tunnels for american cars.
all of this stuff was all R&D spend with ROI to learn how to make tech ready for space mining
think about it .. solar panels(solar city), drilling equipment(boring), moon buggies(tesla)
its all in preparedness of funding asteroid mining for rare minerals.
thats his retirement plan. get rich from space mining, by being the first/main company doing it in space
the end goal is not tesla or solar city. those are just first steps into the R&D required for space mining. where he gets some returns on his investment while doing the research/design
he pretends his 'aspirations' are mars colonisation(as ognasty thinks.. BUT. ), he is not making 'bio-dome' houses nor venturing into farming(oxygen and food). meaning he is not planning on human colonisation..
by venturing into drilling and robots. his goals are more about mining not colonising.
emphasis
his R&D is more about drilling and transport(large yield transport of 900tonne payloads (rare minerals).. yep its about the mining.. not the colonising
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when asteroid 'prospectors' want advice, tools, equipment, transport. they will all buy from tesla as the full service business supporting asteroid mining
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if your thinking 'trillionaire' you are thinking to small.
hyper inflation already made many people trillionaires in many currencies.
US dollar is going to hyper inflate and so trillionaire is the new billionaire.