It's not that the structures are inherently bad, it's that such structures are, philosophically, the exact sorts of things that many early (and current) proponents of crypto wanted to avoid. In that sense bitcoin hasn't
failed as a system in & of itself, but it has failed to achieve the philosophical goals of those people.
Bitcoin & crypto also might not be sovereign in origin but they have plenty of sovereign influence, basically as much as any sovereignty wants to impose on it. Especially as entities like the SEC & IRS come to terms with it, it will be just as vulnerable to government control as fiat currency. This is especially the case because any wide-spread adoption will require adoption by large financial institutions, which cannot avoid regulatory regimes of their local jurisdictions. From the US government's standpoint, US citizens holding bitcoins is not much different than US citizens holding Euros. How that money enters into the US economy & interacts with US financial institutions or changes hands from person to person are basically subject to the same rules & regulations. If you're conducting a a transaction in excess of $10,000 then whatever mechanism facilitates that will still be subject to CTR's, and any "suspicious" transaction of lower limits will still be reported, by law, to the government.
Basically, if you want to convert bitcoin to the local currency to buy something, you'll need to use some sort of off-ramp that will be a regulatory bottleneck. Want to build a "shadow" economy purely driven by crypto exchange? Well, you'll still have to deal with the IRS knocking on your door & saying "You have things of value that you are performing work to receive. We don't care what currency or form you received them in, you received things of value. Give us our cut."
In short, it doesn't matter that it wasn't created by a sovereign authority: The control a sovereign authority can exert over it is, contrary to many of the most philosophical hopes for crypto, indistinguishable from sovereign currency in everything but name & source of origin.
Let me be clear though: I'm not anti-crypto. I'm probably a little ambivalent, and a little optimistic that it might replace high-friction mechanisms that exist in current financial infrastructure. What I do believe is that crypto cannot both go mainstream and fulfill the philosophical hopes that many had wanted for it.