And that's even assuming that Google doesn't 'leverage' its ability to control both software and hardware.
but I do understand I'm likely not their reference target
Every new Samsung offers new features, it's not necessary to buy a new Samsung when your old one craps out. There is little to no lockin. That massive advertising budget is a necessity for Samsung, without it people would forget about it entirely and buy Google, HTC or iPhones.
I can understand why Samsung finds the idea alluring, I'm not sure if they can successfully nurture a 3rd mobile OS in a brutally competitive field where Microsoft/Nokia and BlackBerry failed.
I think the reason coke is pure marketing is because sugar drinks is pretty much a solved problem. No one is ever going to make a drink that is 10x tastier than coke.
Samsung is like Coke, its advertised everywhere and when it comes time to get a new phone consumers subconsciously go for whats familiar.
The apps and what they offer has nothing to do with it.