To me, you still seem to be implicitly assuming that the old person would be reflecting "old" perspectives. I don't necessarily disagree with this assumption, but I think you may be overlooking how much your argument depends on this. And, I am not sure that the dreamers of life extension share this assumption.
Playing devil's advocate: If one had the permanent physical and cognitive characteristics of someone in their 20s-30s, might they not continue to pass as a young person? Unless you look up their identity in some registry, you wouldn't necessarily be able to identify a cohort. Here is urban Southern California, I see plenty of "old" people in their 50s-60s who are trying to pass as young people all the time. What if they don't have to mask fading hair and eyes, sagging or blotchy skin, aching joints, gravely voices, or personality changes?
You describe a person from 200 years ago existing today, as if they step out of a time machine. But, if they have had 200 years to absorb pop culture, mannerisms, dialect, etc. then how would you know? They won't be repelled by garlic nor invisible in mirrors. They won't even be afraid of sunlight (no skin aging!) and their blood-sucking may not be distinguishable from any young go-getter's.
Playing devil's advocate: If one had the permanent physical and cognitive characteristics of someone in their 20s-30s, might they not continue to pass as a young person? Unless you look up their identity in some registry, you wouldn't necessarily be able to identify a cohort. Here is urban Southern California, I see plenty of "old" people in their 50s-60s who are trying to pass as young people all the time. What if they don't have to mask fading hair and eyes, sagging or blotchy skin, aching joints, gravely voices, or personality changes?
You describe a person from 200 years ago existing today, as if they step out of a time machine. But, if they have had 200 years to absorb pop culture, mannerisms, dialect, etc. then how would you know? They won't be repelled by garlic nor invisible in mirrors. They won't even be afraid of sunlight (no skin aging!) and their blood-sucking may not be distinguishable from any young go-getter's.