Until Michaelson-Morley’s landmark experiment, we hadn’t found a way to falsify aether either. Is there physical proof that dark matter is not falsifiable? If not, we still have a bit further to go.
There is always a tension in Physics between physical proof and observability on the one hand, and having the right idea, the right intuition on the other.
Going back to my Einstein example, there were other Physicists who contributed to Relativity (Lorentz, Minkowski, Poincaré, Fitzgerald) but we give Einstein the most credit because he had the right idea, that it's not enough to treat the speed of light as a constant in your math, you actually have to believe the Universe works that way. One of the stories that gets told is the reason Einstein never got a Nobel prize for Relativity is because the Nobel committee just wasn't ready to give it up and credit Einstein with discovering a new, fundamental truth about the Universe.
Another story that gets told is that when Einstein was an undergrad at the ETH in Zurich, Minkowski was one of his professors and he dismissed Einstein for being a "Lazy Dog" because the math never came easy to him. But he looked at how Physics was taught at the time and knew something had to change. And he was right about that.
I'll just leave this here, Feynman explained it better than I ever will.
