Can Outsiders Make an Impact on Science?

Yep.

Note that he was not crushed by a jealous Physics Establishment. If The Powers That Be don't take your theory seriously, it's not because you're an outsider.

He was exceptional in two ways. He was older than the usual ground-breaking researchers and was outside the academic world for a while. Those two facts might go together. I have noticed that mathematicians who make discoveries at relatively advanced ages (Sylvester, Kronecker, Hausdorff) have often spent a decade or two outside of mathematics research. Maybe a fresh look is what's needed and such a fresh look can be regained.