> being able to fork a desktop OS from 20 years prior, make it into a mobile OS, then to a tablet OS, then to a watch and a headset OS, and then have billions of users on it all and make a trillion-dollar company out of it⸺does that not sound like good engineering to you?

Microsoft and Google basically did the same thing, and in neither case it's really a testament to how "good" their respective software is engineered. If the amount of driver cruft on MacOS is anything to go by, the engineering underneath iOS and WatchOS is probably a fucking nightmare in most respects.