> I really only cared about the evolution through ABI Stable.

Ok, but that came later and wasn't present in 2014.

> they did a "hard-sell" with Swift

I agree with that. :-)

> "Full System API" is the native frameworks; UIKit, AppKit, WatchKit, etc., as well as things like WebKit and MapKit.

Swift did of course have bridging to Objective-C and the preexisting Objective-C API. I find it strange to equate language bridging with announcing a full system API — an API originally announced around the turn of the century (can't believe I'm using that phrase now). Cocoa-Java, which no longer exists, also had such bridging, as does PyObjC and MacRuby/RubyCocoa. Still, most of the system API to this day are written by Apple in Objective-C.