Why is it an advantage being Electron? If anything, IDEA is also cross-platform. As for speed, VSC is faster as a text editor, but not that much faster for IDE stuff if you try to use it as that. Even slower some times, maybe LSP incurs some overhead IntelliJ don't have to do.
While I get the point of LSP, as I wrote in another comment an IDE is much more than understanding the AST of the language and providing autocomplete.
I don't get your point about usage. What is it supposed to show? Even though VsCode is growing fast, JetBrains products are also growing and thus has a merit to them?
Usage is important, has all editors live and die by their community. Intellij is less dependant on them, as they develop their most important features themselves, but third-party plug-ins are still mandatory nowadays.
That's my take, anyways. I'm biased as I personally wouldn't use Intellij if not for the community that made Emacs mode plugins for it. I also tend to costumize more than your average programmer.
But tooling becomes broader and more complex year after year (too complex, maybe), so I don't see in the futur any company being self sustained on that front.
While I get the point of LSP, as I wrote in another comment an IDE is much more than understanding the AST of the language and providing autocomplete.
I don't get your point about usage. What is it supposed to show? Even though VsCode is growing fast, JetBrains products are also growing and thus has a merit to them?