I think you’ve got a point here, in that the sort of Devs who want to be able to refactor their code without breaking everything are also going to be the group who lean more into having code that actually runs quite fast; but given that reasonML is awesome and didn’t get much mindshare my position here is that wasm will only start to eat into tyspecript’s lunch well after a huge subset of TS can be compiled to wasm (or maybe python ((I blame the xkcd guy for python’s unreasonable popularity, I feel it’s hugely overrated))).

Absolutely not true. I know this is just my experience, but I’ve worked with plenty of devs who’ve contributed prs and/or donations back to OSS projects in the past, and all my former employers have opensourced at least some of their software

A propos, I actually find that the biggest win of FP is somewhat orthogonal to it, and that’s immutability. This leads to the ability to reason locally about code which is IMO completely invaluable even outside of parallelism scenarios. When you don’t know if a method might be mutating a parameter without actually reading all the way down it’s a real PITA 😅 (I have been doing a lot of refactoring of a large codebase recently and this has been a serious issue)