I strongly suspect the individual would perceive it to be very different from dying, yes---both on the experiential level ("I look at my hands and I'm still here") and on the memory level.
Memories don't randomly vanish; there's pretty good evidence that the brain does retain useful content. So if you're arguing that "500-years-in-the-future you would be such a different person that we might as well say now-you is dead in 500 years," I think the burden of proof is on that claim because we don't make it for modern elderly people. It passes neither the common-sense sniff test nor the extrapolation test ("What's special about 500 years out as opposed to 70 years out that breaks continuity?").
It was not about 500 which I think we can live to, it was about searching a boundless expansion of life -- until a certain time where the physical limit of information stored in the brain is too large
Memories don't randomly vanish; there's pretty good evidence that the brain does retain useful content. So if you're arguing that "500-years-in-the-future you would be such a different person that we might as well say now-you is dead in 500 years," I think the burden of proof is on that claim because we don't make it for modern elderly people. It passes neither the common-sense sniff test nor the extrapolation test ("What's special about 500 years out as opposed to 70 years out that breaks continuity?").