Conservationism is about conserving a place in the world where humans can survive, full stop. It's not just food, it's disease, it's mycology, it's everything, and if we're not careful, we will render the planet uninhabitable for naked apes.

You're right, in the sense that of course the tardigrades, archaea around deep ocean vents, and blue-green algae will continue trucking along more or less whatever happens. We, however, are not tardigrades.