Repeated success along multiple businesses is an objective measure. There is a chance he lucked into paypal, tesla, spaceX, and starlink, but it seems reasonable to assume he is contributing (and detracting simultaneously) something to score 4 successess, even if that is just hiring the right people and making big bets.

These are also hard businesses, dealing with physics, chemistry, and regulations. Unlike SaaS businesses one spins up on cloud services. Which lends some more credence to not just being lucky.

Obviously, he has a reprehensible agenda, but there is clearly a case to be made about his ability to execute.