I agree with you that the enormous cost is probably not worth it, when you start thinking what else could be accomplished with the money in the context of it's low probability of success.

However, those technologies that increase human lifespan are really something entirely different than cryonics, not a replacement for it.

Even if we increase lifespan significantly, as long as we still have a lifespan cryonics would allow us to remain frozen until even more life extension technologies come about. It's also a potentially viable method for keeping people alive for long distance space travel at sub-relativistic speeds.

I'd look forward to seeing a more detailed post (or even a journal article) from you going into the biochemistry specifics of the problems with cryonics you mention in this post, and your other posts in this thread. I am particularly curious why rehydration would denature proteins which are naturally stable in water? And what sort of membrane distortions would occur that aren't reversible?