> Jetbrains' main feature are their own engines.
Jetbrains IntelliJ platform supports language servers and for example, WebStorm will use tsserver for TypeScript code. CLion also uses clangd, and there are also third-party plugins that use the LSP client.
> And MS still has Visual Studio - without Code ;) - which doesn't use LSP.
Microsoft Visual Studio definitely has a built-in LSP client, and yes, I mean "not Code". By default it will be used for tsserver (regular Visual Studio indeed supports TypeScript), and third-party plugins can use the LSP client too.
> And Apple is Apple
Of course, we'll see. Apple is stubborn yes. If they do LSPs, they'll do it their way specifically. That said, I personally think it's decent odds to eventually happen, especially seeing as the Swift programming language provides an LSP.
> On the contrary I'd say that everybody who want's to get "big", must not use LSP to have something that sets the editor apart.
Well, it's certainly possible to build richer features than the LSP can support if you build your code intelligence engine to be tightly integrated with your text editor, and it is true that a huge selling point of IntelliJ is indeed, their own custom code intelligence. However, I think this is a false dichotomy. There is definitely no reason a program that has its own framework for code intelligence systems can't also support LSP - I mean, both Visual Studio and IntelliJ do, and IntelliJ has always been mixing multiple sources of code intelligence together, as it still does today with clangd and tsserver, which in IntelliJ get combined with their own analysis and refactoring tools.
Modelling code intelligence the way Jetbrains always has probably won't go away any time soon, but I think it is pretty clearly not the future. The future is building code intelligence into the compiler, and redesigning the architecture of compilers to better accommodate these interactive, incremental use cases. Jetbrains seems to be a very smart company and I don't expect them to continue to cling to outmoded approaches if they prove to be less effective, and I suspect that as LSPs continue to improve Jetbrains will continue to lean on them and probably even contribute to them.
I will say though, at this point, not having a built-in LSP client does indeed set your editor apart quite a bit, although definitely not in a way that will be favorable!