People have to make a living ... and people, use the best available tools ... if they can ... to make money and earn fame in Secular Society ... where Academics are out looking for "new" Reasons ... Rational explanations of ... the state of "Being" ...
Darwin was no exception ... but his Classification was to become, the latter-day Biologists, Botanist and Ecologists "Basic Tool" ... Thus, he deserves credit, for the huge effort he made in the direction of a certain "angle" of understanding, Reality.
Darwin, used his day's new Tools ... the Microscope and Systemic Classification ... and earned for himself, the Beagle cruises ... and naturally money and fame.
But if he had the Electron Microscope ... his Theory of Evolution, would be radically Different, from what he has presented in his "Origins" Treatise.