I was not obsolete. A big company like Apple, there are always things that need taken care of.
I assumed with iOS, Swift, etc., maybe the guys on the Cocoa team were obsolete? Of course not. That code is still there, still needs maintaining, interoperability with the new languages, frameworks, etc.
I'm more surprised they want to stay on.
And that is in fact why I left Apple: the job had changed, the "career" had changed. The engineers were no longer steering the ship. It had been that way when I started in 1995 though. A "team", let's say the graphics team, would figure out what API to revisit, what new ones to add — perhaps how to refactor the entire underlying workflow. The "tech lead" (who would regularly attend Siggraph since we're talking about the graphics team) would make the call as to what got priority. Marketing would come around after the fact to "create a narrative" around all the changes to the OS. I hate to say it, but many, those were the good ole' days.
(And let's be clear, in the 90's, Apple's customers were more or less like the engineers, we also loved the machine for the same reasons they did — so we did right by them, made changes they would like because we wanted them too. You can't say that as convincingly for the phone, being a mass consumer device.)
Marketing took the reins long ago though — especially as Apple began to succeed with the iPhone (which, someone can correct me if I am wrong, but I think was an engineer driven project initially — I mean most things were up to that point).
I stuck around nonetheless though because there was money to be made and kids still to raise.
When the last daughter flew the coop though, so did I.