VS, Eclipse, Netbeans, Delphi, C++ Builder, KDevelop, QtCreator,...
> Notably, the two-sided market problem was solved by Microsoft, who were a vendor of both languages (C# and TypeScript) and editors (VS Code and Visual Studio), and who were generally loosing in the IDE space to a competitor (JetBrains)
Nope, the IDE space on Windows has always been owned by Microsoft since Borland dropped the ball with their management crisis where to go next.
VSCode and LSP were created out of Monaco and Erich Gamma's stewardship, yep one of the four on the patterns book, and original Eclipse team.
"VS Code an Overnight Success… 10 years in the making"