I'm not too sure why you say Android vendors are in a sweet spot. They're desperately trying to differentiate themselves through form factor and UI improvements, with only Samsung having had success so far. That branding and differentiation allows Samsung to go from near $0 margin to $100+.
The thing that makes it "easy" for Android vendors to churn out phones is also what makes their margins razor-thin.
Also there are plenty of advantages to an Apple-like closed system. It's the same as the Microsoft vs Apple philosophical debate