Scam implies intent and someone benefiting. These cryonics organizations are nonprofits run by members.
By that logic, computers are a dead end because Babbage's Difference Engine No. 1 never really worked properly... Or that space travel is impossible because a lot of early rockets blew up on the pad.
I don't understand this kind of pessimism at all.
It might work someday, maybe. But it won't work now. The corpsicles which currently exist are just as dead as if they were cremated. I understand, sort of, the psychology of people who lie to themselves about this, but that's all that's happening.
You don't know what future technological capability will be. Current Alcor and CI patients are preserved well enough that their bodies and brains could in theory be repaired by technology at the physical limits of possibility. The information is there.
You are saying that existing technology is unable to fix the issues of vitrification. That is correct, but irrelevant.
Cryopreservation of corpses is a scam designed to fleece rich people with an extraordinary fear of death. Some justify it to themselves as supporting research which might lead to effective corpsicles, but to support such research they could simply donate to it. Not waste their money on an elaborate and expensive embalming with no hope of salvation.