What distinguishes the Mac ecosystem over other PC OS'es is that the small number of supported hardware configurations makes it possible to do much more thoroug

What distinguishes the Mac ecosystem over other PC OS'es is that the small number of supported hardware configurations makes it possible to do much more thorough system-level testing and optimization. The result is a much more stable and secure OS. As soon as you start letting users swap out components without restriction, you're going to see user experience decline. EDIT: I'm still fully expecting Apple to allow change-outs of key components through Apple-supplied upgrades.