It seems strange to consider Haskell as dead when its motto was "Avoid success at all costs". Haskell wasn't popular in enterprise settings because it didn't want to sacrifice being a good language for being a popular one. Haskell was/is very successful if you base it on it's own terms. Now, that goal can be debated, it could be argued that an unpopular language is never that good because it is unpopular, but that's a different argument.
Exactly. Haskell has explicitly been run and planned around not being successful because real production usage and success will require the maintainers to limit breaking changes, for example, which defeats its purpose as a language for experimentation and research.
