> While a lifespan has no limits in theory if technology is advanced enough, the belief that it can be achieved by a living person is based on hope rather than evidence.

I would say it's based on fear. Ego. Maybe disconnection, bordering on solipsism, as if living in this world is only meaningful if you personally live forever.

Hope motivates aspirational curiosity. The attitude from some longevity enthusiasts here seems to lean more towards vitriol and tautology.