Spacex couldn't afford to launch Starlink if F9 wasn't dirt cheap. So either it's cheap or some financial strategy is hiding money? EASA has underestimated SpaceX from day one.
EASA is the European Union Aviation Safety Agency. I think you meant to say ESA, the European Space Agency? But ESA's not that relevant here, as the European governments fund and develop launch services through Arianespace, a consortium of space industry companies led by the French aerospace companies Airbus and Safran.
Correction aside, I agree with your point that Arianespace did underestimate SpaceX.