It seems to me that "living forever" is a fairly inaccurate term to use, and the emotional impact from part of the reader's brain taking it literally would make many readers very sympathetic to your argument, more so than if you used an accurate term.
From Mike Darwn's Chronopause, an essay titled "Would You Like Another Plate of This?", discussing people's attitudes to life:
Conclusion, graphs, and references in article. As usual, I recommend reading Chronopause.com as Darwin has many good articles; to quickly link a few: