Apple's current focus is iPhone and iPad.
Microsoft has zero market share in the table market ("there is no tablet market, there is an iPad market"), and a very small share in the mobile phone market.
When you are #1 in a market, you don't do comparisons.
The Apple Stores are probably the best marketing the Mac can ever get. So it's better for Apple to spend money on the stores than on making TV ads for the Mac. And so they have: http://www.asymco.com/2012/06/25/the-face-and-the-brand/