[SkyMarshal]

>Why do people seem to assume that those most capable of implementing the cryptography, networking, or other code are also those most capable of understanding the economics of cryptocurrencies or determining their future?

Imho on average it's easier for computer scientists and engineers trained and practiced at algorithmic/systems/recursive thinking to learn (and invent) the relevant economics than it is for economists to learn computer science. The emerging field of cryptoeconomics is an amalgamation of high-assurance systems engineering and mechanism design (applied game theory), and computer scientists and engineers are on average better equipped to understand both parts of it than most economists are.

There's also an invaluable degree of street smarts and intuition in people who build and work on complex systems of varying non-/determinism and value-at-risk on a daily basis than in folks who just study/model them.

>Bitcoin seems like technically great but it fails on many of the economic aspects (e.g. making a currency with a fixed amount basically ensures it can never be used to write long term counteracts in).

Fwiw Bitcoin's issuance model is what it is b/c Satoshi wanted a strong incentive for people to bootstrap Bitcoin in the early days via mining, and a scarce deflationary currency was a simple and effective means of achieving that. He succeeded obviously. Any problems down the road resulting from that can theoretically be fixed with some kinds of derivatives, or worst case-scenario with a non-contentious hard fork to change the issuance model. But that would require a clear crisis affecting the value of the currency that everyone could agree would need solving, which likely won't be the case for as long as there are non-trivial mining rewards.