Except that they'll quickly recoup that "subsidy" by raising prices after they've dumped their competition.
If you're right, then capitalism is hopelessly bad at optimization and we should scrap it. But what I think is more likely here is that Amazon's execs understands the economics of their business way better than a zero-karma free-market fundamentalist whose pseudonym is a genitalia joke.
Also, I only made fun of your username and your lack of karma because you were making absurd unevidenced claims like, "They have no power to raise prices and restrict competition." If you're going to say things like that, then it's not so much making a point as doing what Frankfurt calls bullshiting. [1] That combined with your very low karma suggests you're not really worth the time of a serious reply. Note the link in my bio: http://www.penny-arcade.com/comic/2004/03/19