You say this, possibly as someone who knows a lot about this stuff but there are plenty of people (including engineers) who don't know enough to refute the bold claims made by the crypto-evangelists and who be convinced that "obviously X is bad, but our product is completely different".
I personally have lots of misgivings about various crypto but I really don't have enough expertise to argue against someone telling me that I just don't understand and everything is fine.
So why is your default position that they are right and this is a new paradigm?
Surely the onus is on those promoting such schemes to convincingly explain their workings; if you can get 20% a year the explanation had better be good...
This is just the last resort of a scoundrel who knows they can’t explain their scam.
I personally have lots of misgivings about various crypto but I really don't have enough expertise to argue against someone telling me that I just don't understand and everything is fine.