Jupyter is great but it's somewhat of a "lowest common denominator". So there is always the temptation to make a more task-specific version; see also the Pluto notebook project for Julia and R Markdown (although the latter evolved concurrently with IPython/Jupyter, not after it).

LSP is in a similar situation right now, where it's great for languages that lacked tooling to begin with (like Python), but it's not yet possible to migrate existing powerful language tooling (Lisp SLIME, OCaml Merlin) to use LSP.