Oh, come on, are you trying to say that all endangered species will just adapt to live amongst humans if their habitat is destroyed? Your idea about polar bears foraging for human garbage is laughable: These creatures are (1) purely carnivorous, and (2) incapable of living in warm climates. Polar bear population has plummeted as their natural habitat has dwindled. Further, the reason for wanting to save the polar bear is not just to save one species, but that this animal's decline is a bellwether for the decline of the entire arctic ecosystem. We can't say for sure what will happen if the arctic ecosystem disappears.

The ongoing massive extinction event driven by human activity is a real thing. Do you want to live in a world where the only animals alive are ones that humans raise as livestock, or that thrive amongst humans? Nothing but pigs, chickens, pigeons, sparrows, cockroaches, bass and such. Sounds awfully grim to me, but without serious efforts towards preserving wildlife, this is precisely what the future holds.