Can we really say that Apple has the market cornered on good, proper, thoughtful, insightful UI design? Specifically, and as it relates to my trajectory as a software engineer, need I be tethered to OSX as a front end specialist/full stack generalist?

I would like to live in a world where UI development is not tethered to any specific software package...the Photoshops...the Illustrators. I would like to live in a world where UX designers design for the browser. I would like to live in a world where UX designers understand the box model(s). I would like to engineer UI components and layouts using pure CSS without the intrusion of sliced images, etc. I would like all incidental elements to be generated from SVG as font files and utilized as characters within the CSS.

So I would like to be able to answer the question that I opened with as a resounding "NO". There is too much to be gained by divorcing UI thought process and engineering from a single OS to continue in the manner we as front enders (and our designer cohorts) have been conditioned to accept as unchangeable. It is all points on the plane, points in space, algorithms and rigorous application of Euclidean and transformation geometry. This is not the exclusive purview of any one operating system OR any one browser.