If society included lots of immortals, they'd be pretty driven to make sure that we're not stuck living on a planet with finite resources. There are plenty of untapped resources laying on the ocean floors and deeper into the Earth's crust than we typically mine today, and lots more off-world. Those are all technologically within our grasp today, they're just not cost-effective. But if we had to support an immortal society, the ROI terms change: it becomes reasonable to invest in an infrastructure that will take a few centuries to pan out, because people will live to see it completed and get the benefits from it.