On top of the usual problems of a project becoming about maintenance and negativity, languages are destined to become diminishing returns and new languages always end up ruining themselves trying to add more to the foundations.

You can see with D, Rust, haskell, and whatever else, the transition to working on an ecosystem with easy to use and polished tools, IDEs, debuggers, autocompletion just never happens. The languages that get heavy use like C++, java and python solved the chicken and egg problem of having an ecosystem at some point where there was an actual workflow instead of just a hacked plugin and a command line.