The Darwin vs Wallace example is completely different from the Newton vs Leibniz.

In both cases, neither stole ideas from the other. However, at least my understanding, is that Newton and Leibniz did the work at the same time, but because Newton already had a reputation, Newton took all the credit. In the case of Darwin vs Wallace instead, Darwin had years and years of research, notes, and writings done but unpublished, but he rushed to publish when he heard that Wallace had similar ideas. So in a sense, Darwin didn't walk away with more credit than he deserved, as he was there first anyway. Newton vs Leibniz doesn't look as clear cut.

(By the way, in before Edison vs Tesla, that's yet another entirely different situation of plain exploiting and stealing of Tesla by Edison)