And he's also proven himself with X, Boring, SolarCity, America PAC, PayPal etc.
We can agree that he is an asshole and also acknowledge the fact that he has a statistically significant success rate for big engineering tasks.
b) SolarCity has been unquestionably a failure.
c) America PAC which handles most of the field operations for the Trump campaign has been in the news for how poorly it has been managed.