Tesla was founded as an electric carmaker by engineers Martin Eberhard and Marc Tarpenning. Musk was an early investor and Board member - a venture capitalist. Then Tesla CEO.

Musk purchased 'X', formally Twitter. Twitter was created by Jack Dorsey, Noah Glass, Biz Stone, and Evan Williams in 2006.

Thomas John Mueller an American aerospace engineer and rocket engine designer was the mastermind behind SpaceX. Musk funded SpaceX. Musk does not have a degree in engineering, but Musk has a lot of family money. Musk seems to enjoy the influence of a 'shit-load' of money.