If we are to become a spacefaring species, it will be up to the private sector to make it happen. NASA, in my opinion has lost its focus and its mission is being dictated by (edited for political correctness).
As for humanity's value to this planet, I would suggest to those who think that Earth would be better off without humans set the example and let the rest of us decide whether or not to follow.
(Note to the BBS: I am in no way advocating suicide, homicide, genocide, or any other -cide. Just making a point for the amusement factor.)
This planet was designed so that humanity can thrive. Just look around. If you don't see it, I can't help you.