Comment by crabbone

Well, I'm not there yet :) My knowledge of both languages is quite superficial. And, unfortunately, it tends to stay that way, unless I work on a commercial project in a particular language. I sort of worked on a Rust project, but I barely touched the Rust code (mostly the automation around it). With Ada, I don't expect to ever find a job that requires it...

As for the "proprietary" part, this is my understanding, which might be totally wrong, and maybe some VSCode users will correct me (I don't use VSCode):

Some LSP servers are proprietary (even though the protocol itself is open-source). Furthermore, some VSCode extensions (which is what LSP servers usually are) are both closed-source and have a license that only allows them to be used with VSCode. So, other tools that can interface using LSP won't necessarily have as good of a support as VSCode. LSP being a complex interface means that it can be implemented to a lesser degree by any individual server.