Thats not the point of the article. Its because Google and Amazon are subsidizing the cost of their tablets so much that the consumers are expecting other manufactures to do so. Apple can get away with it because of their market presence and the idea that they are a quality product.
Your right, the Nexus 7 will explode the tablet market but who OTHER than google/Amazon can subsidize the price point to 200 bucks? This is why Dell and other manufacture companies jumped ship. The OEM's sell hardware for a profit, they cannot compete with companies that don't care about the hardware cost when they make up for it on content distribution.
Hell, this is why Microsoft is giving the finger to all the OEM's when it comes to their tablet. They will either have to subsidize the tablet to make it a "cheaper" alternative OR spend the time (years) to keep it on the market and compete with Apple directly on features and not on price.
If you want a real example of this, look at the US Cell Phone market. People EXPECT free phones with a contract or pay just a little more for a higher quality phone. However, if you look at Japan or Europe, those same phones are bought at full price for cheaper service.