Wannabe's never do the thing. They don't seriously try to do it. I have no reason to defend bezos but people made a serious effort there and they would not be wannabes even if they failed
I'm a wannabe for launching weather balloons and model rockets with my kids from the comfort and security of my well paying public sector job
However, I do not agree with your definition of wannabe. You can seriously try to do something and still be a wannabe. Bezos has seriously tried to do this, but I don't think he can cope with the notion that while he is enormously successful (by many metrics) at Amazon, he may not be the right person to lead a space company.
Webster's definition of wannabe 1 : a person who wants or aspires to be someone or something else or who tries to look or act like someone else 2 : something (such as a company, city, or product) intended to rival another of its kind that has been successful
SpaceX doesn't own space, of course not. But BO isn't even a serious player yet despite 21 years of effort. SpaceX got to orbit on the fourth flight attempt, after 7 years of effort. Despite Bezos' protests to the contrary, it isn't even a contest.
Plenty to not like about Musk, but SpaceX is enormously successful.