I was talking to a friend who has been looking into cryonics. I'm skeptical for the reasons below. This has nothing to do with the good faith of the cryonics companies around today, but with the incentives of future generations.
The claim of cryonics as I understand it is that
It is possible to freeze an ailing human body (or part thereof), wait for medical technology to progress to the point where it can be returned to good health, and then revive it.
This is a reasonable course if all the following hold
(1) that there is an appreciable chance of being revived
(2) that the person revived will survive for an appreciable time after being revived
(3) that the person revived is very similar to the person frozen
(4) that the time at which the person is revived will appeal to the person being revived
I think these 4 assumptions are unlikely to hold at the same time.
A person is frozen, and in their children's or grandchildren's lifetime are revived. In this case, I think 2 is unlikely since medical technology will not have had time to advance much. This may not hold for people suffering from very particular afflictions, especially if they are wealthy and create a foundation to use their wealth to seek targeted advances.
A person is frozen, and in the distant future, medical technology has solved their affliction. In this case, I think 1 is unlikely.
I assert that never in human history, has human civilization produced a machine with a moving part that has continued to function for 100 years without regular maintenance.
This means there is a trade-off between cost of maintenance and cost to revive. Consider two ends of the spectrum. If a cryogenically frozen person is buried in a particularly slow-moving glacier, then maintenance costs are low, but cost to revive is high. If a frozen person is warehoused, then maintenance cost is high, but the cost to revive is lower.
I argue that no-one who would be able to revive them would have economic incentives to do so with a few exceptions that I discuss later.
If the frozen has no assets then noone has incentives to keep the machines running.
Who has either legal standing to act on behalf of the frozen, or economic incentive to see someone successfully unfrozen? Very few.
The cryogenics company has an annuity as long as someone stays frozen. If no next of kin can be identified, the cost of losing an annuity due to death is probably lower than the cost of successfully reviving someone. The cryogenics companies' business models are basically like a family that keeps cashing welfare checks for a grandmother who is disabled or dead.
Lawyers working for the frozen's estate have mixed incentives. Law firms conglomerate like other industries, so after a certain amount of time, the number of long term cryogenically frozen clients whose estates are not administered by a law firm that specializes in frozen clients will be small. They can charge an annuity, and when it comes to decide whether or not to revive, they run the risk of killing a paying client and ending their annuity or continuing to collect a check. A law firm that specializes in such things will have internal controls set up so that they act in the most risk-averse way -- they will never revive anyone unless someone else with legal standing threatens to sue.
Who might have such standing? The RIAA. Since fashion is fickle and cyclic, the RIAA might succeed in getting frozen artists revived so that they can do reunion tours and then, oops their cancer comes back right on cue, and they have to go back to sleep.
Finally, is there a marketing incentive? Not in scenario B. A cryogenics company will want people to have the impression that their latest&greatest are the most reliable, so they will bias to later models. And they will want to use in their marketing literature pretty people who their current target markets can relate to, so will again bias to recent customers.
The above is largely based on arguments from ignorance -- who might have economic incentives? -- but I believe such arguments are valid because I am discussing whether it is rational to do this today, not whether it might be rational for someone in the future.
There are obviously incentives other than economic and legal. If you are a famous scientist, politician, or religious figure, other
incentives apply. For scientists, the likelihood of being unfrozen decreases as your field progresses past your current skill. As a political figure, (4) is problematic since you're just as likely to be revived to stand trial as to be lauded. As with many things, the best course seems to be a god, but ancestor worship is unreliable since current ancestor worshipping cultures do not have to deal with the likelihood of their in-laws coming back from the grave unbidden.
Finally, is a hugely rich person likely to be revived? I doubt it. They are an annuity while frozen, and an unknown political threat to the powers that be if unfrozen.