As many of the comments have pointed out the point raised is not the only viewpoint. Running with the new situation from different angles could have produced fruitful thought that could have been applied with the post.
Cryonics has details worked out while the hydronics hasn't. Thus it's somewhat likely that you are comparing the weak points of cryonics to good points of dryonics. Hunting for a better method it's all good but it can make the comparison accidentally better than it would be after a closer investigation. The cryonics side of the comparison is fixed while the new method side works with just what is apparent.
Say that I think of methods to move in space beside rockets. I might think of dropping behind nuclear bombs to improve energy extracted per mass used. This might be all nice while only thinking about pushing a craft forward. However if I stop to think about other implications the situation doesn't seem too rosey: there might be radioactive products left behind, there can be significant forces to nearby other vessels or habitats, it would be trivial to weaponize. These disadvantages might be overcome with some design but it's far from "go faster" kind of magic button. And I don't need high technical abilitity to realise that those sorts of drawbacks are possible.
With dryonics it likely needs some support from cell chemistry. Changing the cell chemistry on a already alive human could be somewhat messy. And even if it would be adjustable it is somewhat likely that human cells do interesting things that conflict with such "design constraints". How much immune system efficiency, alcohol tolerance or metabolism speed would be ok price to pay for the advantage? Even if successfully dried people would require less energy upkeep protecting them from erosion might bring the cost closer to high tech upkeep. At room temperature the surrounding bacteria can be active. Would they be vulnerable to winds, sounds or earthquakes?
If we only want methods that work in principle regardless of details you can always plan for a round trip in the stars to use the twin paradox to be subject to the expertise of future doctors. The question is only whether the details of time dilation, cryonics or dryonics are doable. Thus skipping or being ignorant of the details doesn't help that much. Finding a new preservation mechanism mainly extends the frontier where concrete progress can be made. So eventually before long you have to dig deeper. And doing today what you could do tomorrow ensures you don't get stuck in the past.
I certainly didn't intend to imply that this was the only viewpoint, or even that it was necessarily better, only that it addressed some of the issues with what seemed to be the only current possibility. I agree that it would require considerable research into how to achieve it: my point is that these would be upfront costs, whereas cryonics has backloaded costs (technological as well as financial). I also did not mean that a "hydronically" preserved organism (I like your term) could be stored anywhere, simply that it is easier to establish pas...
If you don't believe in an afterlife, then it seems you currently have two choices: cryonics or permanent death. Now, I don't believe that cryonics is pseudoscience, but it's still pretty poor odds (Robin Hanson uses an estimate of 5% here). Unfortunately, the alternative offers a chance of zero. I see five main concerns with current cryonic technology:
So I wonder if we can do better.
I recall reading of juvenile forms of amphibians in desert environments that could survive for decades of drought in a dormant form, reviving when water returned. One specimen had sat on a shelf in a research office for over a century (in Arizona, if I recall correctly) and was successfully revived. Note: no particular efforts were made to maintain this specimen: the dry local climate was sufficient. It was suggested at the time that this could make an alternative method of preserving organs. Now the advantages of this approach (which I refer to flippantly as "dryonics") is:
There is one big disadvantage of this approach, of course: no one knows how to do it (it's not entirely clear how the juvenile amphibians do it) or even if it would be possible in larger, more complex organisms. And, so far as I know, no one is working on it. But it would seem to offer a much better prospect than our current options, so I would suggest it worth investigating.
I am not a biologist, and I'm not sure where one would start developing such a technology. I frankly admit that I am sharing this in the hope that someone who does have an idea will run with it. If anyone knows of any work on these lines, or has an idea how to proceed, please send a comment or email. Or even if you have another alternative. Because right now, I don't consider our prospects good.
[Note: I am going on memory in this post; I really wish I could provide references, but there does not seem much activity along these lines that I can find. I'm not even sure what to call it: mummification? Probably too scary. Dehydration? Anyway feel free to add suggestions or link references.]