I think thinkers that imagine the future and figure things, that we can do today, to make life as good as possible for future generations are the ones who keep hope alive. Humanity may or may not survive without people with foresight, but if humanity wants to continue without considerable suffering then we need to make a plan that will counter the actions of the past and present. We are currently on the course for probable extinction, and we wouldn't be going out alone. We would drag the majority of life with us.