For me, the success of models built upon evolutionary notions and used for entirely different things helps point to at least some of its validity.
The various evolutionary landscapes such as fitness landscapes, adaptive landscapes, and watching primitive version of the notions operating in cellular automata (game of life, Stephen Wolfram’s entire body of work), evolutionary modeling of human social systems and markets, even the rise of statistics historically as a legitimate field in mathematics …
… even IF it turns out Darwin was spectacularly wrong, the very many models based upon and inspired by his origin theory which have found function in so many places shows that at least these ideas were useful in many other ways and would continue to be even if he was wrong about the origin of species itself.
In short, I don’t mind if origin of species turned out to be wrong at all.
But I wouldn’t want to lose the marvelous modeling tools inspired by origin of species.