While those community management issues probably didn't help, I don't think Elm's failure to break out can be placed purely on their shoulders. The big reason

While those community management issues probably didn't help, I don't think Elm's failure to break out can be placed purely on their shoulders. The big reason why it - and all the other typed/functional compile to JS languages (PureScript, Reason, etc.) - remained niche is because TypeScript came along. It integrated with the ecosystem more seamlessly, was instantly comfortable for JS devs, and was backed by MS who gave it first-class support in VSCode. Arguably TypeScript is not as good as those other languages, but none of them are better enough to overcome those network effects.