Human achievements only matter to, and improve the lives of, other humans. There's no Best Species On Earth award which we win every year, like the US winning the World Series.
Who, apart from us, says we're so special? God? Darwin? A select committee of chimpanzees and dolphins? Yes, we have more abstract knowledge than we had 1000, 100, even five years ago, but it means absolutely nothing to anyone but us. Our achievements please us alone, and when we become extinct (most likely by our own hands) our vanishing will actually improve life for other species, provided we haven't wiped them out too.
Edward O Wilson was making a similar point:
“If all mankind were to disappear, the world would regenerate back to the rich state of equilibrium that existed ten thousand years ago. If insects were to vanish, the environment would collapse into chaos.”