Getting people to invest money in crazy ideas that have no hope of working was also Elizabeth Holmes' gift. It's not rare or even that difficult. Now Musk has had previous successes, but I'd hardly call electric cars or even rockets and satellites genius or novel. The sad thing is that while he focuses on this, he's not only wasting his money and time, he's wasting the time and money of all the fools who believe that's it's possible and desirable, diverting what could be resources for fixing our own planet. That is the exact opposite of genius and that's why he rightly gets criticised for this insane idea. This Mars idea is no different than Theranos' product. In fact, it's a lot less likely to ever happen.
"fixing our own planet" is not a problem of resources. It is a problem of politics. Most of the people working on space (Musk included) are not that good at politics. They are working on hard problems instead of impossible ones.