It's not even accurate (to the extent that any counterfactual can be considered accurate). If Christianity had never existed, would that have prevented the fall of the Roman Empire? Unlikely. Even if it had, were the Romans in the 3rd Century AD making huge strides in science before Christianity came along? Nope. And you'll note that when modern science did eventually arrive, it showed up in the Christian part of the world rather than the other 90%, which suggests Christianity can't be retarding scientific or technological progress that much.