Apple Stores are a big part of Apple marketing. The service received a these store can range from exceptional to terrible. They don't pay the people who do technical support or work in retail big bucks either.
I am not surprised Apple is doing so well, given the premium they charge for their devices.
The fact that they hire those people at all represents an expense and a service that Android manufacturers just don't have. The operating costs for an Apple store are probably higher than Nexus 7 retailers like Gamestop, Sam's Club, Staples, Office Depot, or Kmart--and the level of service is largely a step ahead as well. Either way, it's still an expense that isn't accounted for in manufacturing margin, which was the original point of the exercise.
Apple uses its giant scale to literally buy up all supply of lots of components and other resources (factory output, air freight, you name it). It's tough to compete.
Walk into the store and you'll see that the best phones from both Apple and Samsung cost the same amount.