I'm not going to spend much time on the issue of Larry Johnson, his book deal, or the veracity of his claims. The evidence seems to contradict his side of the story, but even so I wouldn't be surprised if there were at least a sliver of truth to his accusations. Alcor is a large organization with a long history, and it's run by humans; it probably has a few cryopreserved bodies in the closet.
But cryonics is the topic of choice today because, no matter what problems there may be with the institution, I simply cannot understand how fewer than 200 total people are currently preserved. That's 200 out of the hundreds of millions of people who have died since James Bedford became the world's first frozen human in 1967. There are those that are waiting in the wings, of course, but the three big cryonics organizations in the United States have only a couple thousand members between them.
I am continually confounded by the idea that people are universally willing to accept their own mortality. I'll go ahead and admit right out that the prospect of death scares me more than anything else, and I understand that is not necessarily true for everyone else. But very few people do, in fact, want to die. (The outrage over Obama's "death panels" should be evidence enough of that.) So why are so few people doing anything about it?
Doubt that cryonics is the answer to death is certainly one valid objection. So far, no human or animal has been successfully revived after preservation, although no one has actually attempted to revive a human. Scientists are also not sure if damage caused by ice crystals and ischemia is repairable, but the newer process of vitrification hopes to avoid ice crystals altogether. Further, prospects for reanimation tend to call upon the panacea of nanotechnology or the possibility of whole brain emulation. At present, these technologies can do nothing more than tell you what you're going to die of and maybe simulate a rat's neocortical column with massive supercomputers.
But none of that changes the fact that there are no physical laws of the universe that prohibit the process of reanimating dead tissue. We are all just complex organic molecules comprised of the elements of nature. Given the right stimulus, those elements (barring quantum mechanical effects) will react accordingly every time. I have no doubt that at some point in the future medical science will be able to breathe life into dead tissue once again. The more difficult question to ponder is what is lost in the interregnum between suspension and reanimation.
Here the question of consciousness arises. Even if future scientists can revive the cryopreserved, skeptics wonder if the awakened person behind the Cartesian theater is the same as the one put into cold storage decades or centuries prior. If a consciousness is discorporated when brain function ceases, is even the prevention of information-theoretic death enough to ensure that the same consciousness manifests later?
I will not dwell long on this criticism of cryonics because the mind-body question is a very old one that would distract me for many pages if I let it. Suffice it to say, I believe that there is no empirical method of evaluating consciousness and its continuity, whether between life and death, sleeping and waking, or one moment and the next. While it's certainly possible that your "own" consciousness cannot survive the transition of cryonic storage, the claim is non-falsifiable and cannot be used to inform rational decisions.
Beyond medical and philosophical objections, there is a more pragmatic aversion to the steep cost of the procedure. Cryonics companies require annual membership fees in the hundreds of dollars and lump sums upwards of $150,000. For a service with a 0% success rate at present (but no complaints from customers!), that is a daunting price to pay. The easiest way to mitigate the expense is through the purchase of life insurance policies, which are very cheap when young. But squandering your money on a cockamamie idea instead of providing for your loved ones is not terribly appealing to most.
To the transhumanists and singularitarians out there, however, this objection cannot hold up. The post-scarcity (or human) world that will exist after the singularity should obviate the feeling that you need to supply your family with anything once you're gone. And if you hope that your children will be the beneficiaries of human enhancement in a world without a singularity, the only realistic possibility is that you are already rich and able to afford the life extension treatments, bionic limbs, and neural implants of the future. In that case, a hundred and fifty grand is just a drop in the bucket.
Returning to the high price of cryonics, however, it's important to understand that the 200 current customers are essentially early adopters. As more people choose to experiment with cryonic preservation, the costs will come down due to economies of scale and the refinement of the product that increasing demand allows.
Without valid medical, philosophical, or financial objections to cryonics, I can think of no other reason to avoid it other than pessimism toward the future, which is timeless but nearly always absurd. Even though the science fiction genre is the primary source of dystopian ideas, I believe science fiction also shows us the promise of a brighter future. And if nothing else, cautionary tales help us to avoid potential mistakes. What more could you do to ensure a better tomorrow than to live it?
Cryonics supporters often call upon a decision matrix to demonstrate that, really, opting to have yourself cryopreserved is the only smart choice. It goes like this: if you freeze yourself at death but future technology cannot revive you, then you're still dead; if you freeze yourself at death and future technology can revive you, then you're alive; if you do not freeze yourself at death, you're dead. Regardless of the low chance of success, the philosophical issues, or the high cost, attempting to avoid death at least gives you a chance of doing so. The results of the alternative are clear.