You hit the nail on the head. This is why no one in the Android market can touch them
Its much more than this.
A lot of countries are dominated by Samsung (considering among Android OEMs) mainly because they covered many price points.They always cared very well about low end market.Nobody touched Samsung at low end except Nokia which was already heavily established.
Samsung captured lot of "Potential buyers" into their hands too easily.
They mimic Apple's strategy of how they pulled existing iPod Users into iPhone's world by saying that iPhone is an "iPod , Phone and Internet Communicator"......
Samsung's strategy is something like people will buy low end devices like teens , younger generations and tomorrow they move into high end phones like Note or S series because they are familiar with Samsung's software/skin etc.
Its something like "You get similar phone design and software design from top to bottom at every price point of Galaxy".
Grand , Note , Galaxy , Ace etc. all look pretty much same in looks and also software is ridiculously familiar and similar.When such users go out and see some other device , they suddenly feel alienated or different etc.
Just see how people opposed Windows 8 , lot of people still love start button etc. all that familiarity , So OEMs like Lenovo are putting start menu/button and selling laptops etc.
Another point where Samsung succeeds at high end is differentiation :
AMOLED screen , SD-slot , removable battery etc.
A person finds AMOLED much more attractive than LCD because of vibrant colors.He chooses Galaxy.
Yes , When I walk into a store (multi-brand or Samsung store) , I see atleast one Samsung guy who is ready with demo piece to show to people.They get some sort of commission for selling each Galaxy device.
It takes much more than Marketing to manage all these.