"ANOTHER nature preserve?! But I want a second home!!"
Yes. But part of the problem is that the intellectual, religious and political elites of earlier centuries failed in their duties. In their complacence and lack of direction, they failed to ensure proper acculturation of sane social ideology. In this void, others stepped in and asserted the ideologies of humanism and utilitarianism. These norms now form the perspective you're describing. The problem, then, is one of people's expectations. Everyone (including most 'intelligent' people) has been trained to think this way. So they need to be retrained.
Anyway, if we're going to talk about what is and is not realistic, how is it that you expect to convince enough of the population to kill off everyone below a certain IQ?