Newton's theory of Gravitation stood for almost 230 years before being superseded by GR. During this time it was proven right over and over. And in fact in many

Newton's theory of Gravitation stood for almost 230 years before being superseded by GR. During this time it was proven right over and over. And in fact in many ways what happens with great theories is not that they are proven wrong, but rather that they are extreme conditions where there predictions deviate slightly from reality. In the case of gravity I believe one of the very few deviations from Newton's gravity known was the precession of the perihelion of Mercury - there was not that much known that was wrong about it. I think it is fair to at least hope to find deviations from GR which would have to be at much more extreme conditions given the greater precision of today's measurements.