I maintain that that would've been much harder to implement, for VSCode and for all other editors that followed. Among other issues, it would require a separate

I maintain that that would've been much harder to implement, for VSCode and for all other editors that followed. Among other issues, it would require a separate JVM process and some way for other languages to bind directly to JVM interfaces in that process, since most non-Java editors are not written in JVM languages. If what you're suggesting is an LSP that wraps any given IDEA plugin and maps it to the LSP protocol, well, that can still be done (assuming it could ever be done) and would've still required the LSP protocol to be invented first. On top of all that: you're welcome to re-use any code out there (in any language!) when writing an LSP. Nothing stops you from leveraging the bulk of an IDEA plugin, or whatever generic compiler utilities go into IDEA, when making your own LSP. I wouldn't say any work is wasted at all.