The reason to use LSP is that there are already many existing implementations of it. Starting over with a new protocol, and replacing implementations for all t

The reason to use LSP is that there are already many existing implementations of it. Starting over with a new protocol, and replacing implementations for all the existing editors and languages would be a tremendous amount of work for relatively little benefit. And either forking lsp, or creating a new protocol would cause fragmentation. Also, VSCode is popular enough that even if the other editors forked LSP and made significant improvements, if VSCode wasn't on board, it would be a tough sell to get many languages and existing LSP implementations to adopt it.