and cryptocurrency with some baked in inflation metric is even more ideal
This is not true for several reasons.
#1 - There's no way cryptocurrency resides lower on the base of Exter's pyramid than real, existing commodity currency like gold and silver. So cryptocurrency will always just be the bad money that drives out good money. A civilization that skips the middleman and only uses good money is obviously more efficient since everyone will just be wasting time and resources constantly arbing between each one. I mean gold and silver circulated in native form as coins. Any digital form would just be a receipt to claim your metals in person. Cryptocurrency is not trustless so there is no benefit or difference in efficiency.
#2 - The only way you can actually build a valid cryptocurrency is by
usury proofing it. The ability to practice usury in a cryptocurrency is just a sign you've created a Rube Goldberg machine that accomplishes nothing as I talk about here:
Let me start off by telling a story. At the height of peak-altcoin, a guy I know released some garbage coin with the sole purpose of trying to make money in a pump and dump. I told him, hey, why are you making this stupid scamcoin? His response was, "just what exactly are we trying to do here?" (i.e. being involved in cryptocurrency in the first place).
Before you try to create or engineer something, you first have to actually identify the problem you're trying to solve. The problem to solve is not decentralization, it's creating an alternative to rent seeking usury, aka slavery.
The current state of cryptocurrency consists of closed entropy systems like Peercoin, which are internalized proof of stake, and open entropy Bitcoin PoW systems, which are just externalized proof of stake in practice, not decentralized. Both are stake based and stake based systems have the following attributes, they're designed around someone monopolizing a variable then practicing rent seeking usury on everyone else.
The internalized stake is basically world domination on cruise control and should be shunned by anyone who doesn't want to be a slave, while the open entropy system of Bitcoin tends to give you the same result when you're just externalizing your metaphorical stake into the Pareto principle of the real world. This means cryptocurrency solves really nothing in it's current state, and things like physical silver coins as a currency would be vastly superior in terms of both decentralization and avoidance of usury or seigniorage fee.
Having said that, if you were to try and improve on cryptocurrency in some way, you would be required to remove the stake variable entirely. A system where you can't gain capital by leveraging assets on cruise control with no human intervention or attendance required. The only way to do that off the top of my head is either unprofitable PoW (which seems like it wouldn't work in practice) or by having all senders of transactions solve some type of decentralized captcha or other proof of work that cannot be put on cruise control for profit.
Please revisit my quoted sentence. It is a bit more subtle than you might have thought it was.
The mechanism design of bitcoin is lacking, because of 2 issues that arise as the natural incentive mechanism for securing and using the network respectively: selfish mining and undercutting. The conclusion of these is that "cryptocurrencies should make the block reward permanent and accept monetary inflation as inevitable". Coupled with the fact that Nash's ideal money concept uses the idea of inflation based on quality of the transfer metric we can arrive to my sentence I alluded to earlier. With cryptocurrencies it is indeed possible as I am going to prove with my own project in a few days.
is a good link from which i took that quote from Arvind Narayann the writer of the paper.