With the decline of Apple hardware, this is less true, and modern Linux hardware support is, at worst, no worse than what other OSes provide, in my experience.
> Navigable by non-experts, even when things turn to shit
I think the "Closed Box Philosophy" of Apple either defines or disproves this: Non-experts can't be tripped up by having to fix things... because nobody outside of Apple can fix things, eh? Can't screw up something you're not allowed to do.
> The achilles heel of the open source community stems from the lack of a unifying vision and a top-down approach.
This means that I can keep running Window Maker and nobody can take it away from me. In a broader sense, I'm not afraid to upgrade for fear of losing some part of my workflow due to a high-level decision taking an option away from me. I can use Emacs even if everyone else around me is using Vim, I can use qutebrowser even if nobody knows what the fuck a "Cute Browser" even is, I can write in Ruby even if the Current Dogma is JavaScript.