This is genuinely not obvious to me. What convinced you of this? Or, what do you think the world would look like if there were people who actually had a strong, reasonable, non-insane suspicion that they could do the things that cryonics people <i>claim</i> to be able to? To me, it looks like we are living in that world. Have you e.g. looked through the information, studies, and arguments on the Alcor website?