Immortal of course doesn't mean impervious. A long, unaged, productive life span would still require food, water, shelter, and some amount of safety.

One of the most common (and usually loudest) arguments I hear against general species-wide immortality is the resource limitations of Earth. Well, if we can live for a thousand years or ten thousand years, what's the purpose of not traveling interstellar distances? The major limits are mostly the lifespan and related issues after all. The rest is mostly engineering. We're good at engineering our surroundings.