An advantage that we cannot be sure exists to begin with since SpaceX isn't piblishing financials. And for some launches Arianne Space is already now competitive using the Arianne 5, by all means an out dated design, one that was initially intended to carry a European space shuttle into space.

More generally so, I have no idea why people expect any company to own a market completely. Any market is usually big enough for one than one company to be successful.