The cryonics movement may turn to ashes in another couple of decades any way because no one wants to discuss other looming crises, as I see them:
1. Extracting and discarding the "pseudo" component from cryonics' scientific justification, and quickly. This includes the smoke and mirrors about nanomachines. The longer we let this slide, the greater the risk cryonics organizations will come under legal scrutiny from the perception that they knowingly make fraudulent claims.
2. The lack of a serious effort to maintain institutional continuity. Every time Alcor, at least, has had to replace a CEO during its Lost Decade in the Twenty-Aughts, it looks as if the board had to a scramble to offer the job to a random warm body in the Acoma Street building, with lackluster results. A rational organization would immediately start to find, train and vet at least one replacement CEO who could step into the job on short notice, and then repeat the process to find his or her replacement, etc. This would help to protect the cryonauts in those dewars, the board could implement it now, and it wouldn't cost much compared with physical forms of security like hardening the patient care bay. It would also have the benefit of making Alcor look, you know, competent. I have seen little discussion of the problem of creating the "apostolic succession" needed to make sure that when we wind up in those dewars, we will have people willing and able to look out for our interests in the coming centuries.