It’s really all about the team size. For my personal side projects, I prefer IB, since that’s way faster. At work, where we have 70+ engineers contributing to the same codebase, using IB would be a nightmare. That’s why the leaders you mentioned (and many others) are not using IB and won’t be using it any time soon. I think Android’s approach on “interface builder” is clearly superior. Apple really screwed things up in this area.