I agree with what you say, but the rest of the discussion could go essentially unchanged if the line

Yes, definitely, if a few plausible assumptions turn out right.

were replaced with

"Perhaps, my best estimate of the odds are 1% or so"

(which would be my response in an analogous discussion)

I think that what seems to me to be the main point of the dialog,

"And what disease is this that you can somehow fight with a $28,000 necklace?"

Mortality.

"But ... but ... that's not a disease!!!"

Looks like someone gets tripped up by definitions a little too easily...

is fairly insensitive to a wide range of possible odds for cryonics working.