They are, slowly. Swift is open source, clang is open source. They are moving parts of the xcode IDE into open source, like with sourcekitd and now recently clangd.
I don't think they will ever move 'secret sauce' into open source, but infrastructural things like DBs and dev tooling seems to be going in that direction.
I don't think they will ever move 'secret sauce' into open source, but infrastructural things like DBs and dev tooling seems to be going in that direction.