The evolutionary model says that modern smallmouth bass should be as far from "some Devonian fish" as modern mammals and all other modern descendants of "some Devonian fish." Why? Because the last time everything was together was before amphibians diverged from fish. Perhaps a better answer would have been, "There has been just as much time and about as many generations in the line leading from the Devonian fish to the smallmouth bass as in any other line, so why wouldn't there be a corresponding number of neutral mutations?"
Placemarker.