is they have different primary customer bases.

Microsoft's primary focus is the corporate enterprise customer. That is where the cash flow comes from. Direct individual users are a secondary concern.

Apple is just the opposite. They are a consumer oriented company, which has made few inroads in the enterprise market.

When you go to the Apple/PC store, you are only getting the consumer side of the equation.

I'm not saying Microsoft does not need to do better with consumers - they absolutely do. But individual consumers are such a small part of the Microsoft pie that comparing PC stores to Apple stores is not really that significant.