1) First of all, are we discussing crypto as a currency or blockchains as a technology? Your criticisms seem all over the place here.
2) Maybe talking negatively about the dangers of deflationary currencies while we're in a period of economic inflation and peoples' purchasing power is being deliberately destroyed is not the best idea.
3) I'm not convinced that deflation in a currency is a bad thing. Mainstream economics schools hate deflation, but the Austrian school writes very favorably on the merits of deflation: https://mises.org/library/deflating-deflation-myth
4) Proof of work might or might not be around in the future: who knows? But that doesn't mean that blockchains are unworkable, just that one implementation might not stand the test of time.
> No system that relies on human inputs can prove to be perfectly transparent or eliminate corruption.
Look into what Oracles are and how they can guarantee the reliability of information and the concept of cryptoeconomic security. Who knows where this ends up going and if it's widely used or not, but there's a very high chance that all of the theoretical objections you would make here have been addressed.
Blockchains require an incentive for members of their network to maintain a copy of the shared ledger. Modeling it after a deflationary currency creates a first-mover advantage that generates this momentum. We're not talking about "theoretical objections" or hypothetical better systems, the commonly implemented blockchain systems are creating problems that are manifesting themselves today, and every ounce of capital invested into them creates real inertia against changing how they fundamentally work.
>Proof of work might or might not be around in the future: who knows?
We can not afford to be ambivalent about how this technology evolves.
That is precisely why this is such a societally detrimental technology. The communities that are forming around it are self-reinforcing and suck up both monetary and intellectual capital.
All of this hype about crypto's "potential" is demolished in Dan's excellent work.
>It's a lack of imagination to think that because crypto is "slow" now (and not all of it is by the way), that it will always be the case.
Proof of work combined with the deflationary nature of these currencies is literally the antithesis of efficiency. The system necessarily needs to become less efficient over time because new coins need to become asymptotically harder to mint.
>Maybe a purely decentralized system cannot.
It's clear that the systems that interpret the blockchain (and even the blockchain itself, if wealthy and well-connected folks decide to fork) can be pressured into "censorship."
>if they can prove perfectly transparent and reduce or eliminate corruption?
No system that relies on human inputs can prove to be perfectly transparent or eliminate corruption. The blockchain itself can have provably unbreakable crypto that prevents man-in-the-middle manipulation of data but that in and of itself does not govern the interface between the chain and the people feeding it data.