All right, I concede that there was more rhetoric in that post than substantial argument. Let me explain.
What I mean is, these phrases implicitly belittle the political aspect of every economic issue. We can only vote with our feet if the markets function well, and that only happens with proper regulation (including, but not limited to, antitrust regulation). That, in turn, depends on us voting for the people who will enact such regulation. You know, politicians working for the common good. They are, at the very least, a major theoretical concept.
If the system is skewed (say, by entrenched quasi-monopolies or duopolies, or cartels like the MAFIAA), you can't fight it from inside. You need to change the rules of the game. In principle, democracy means that the people make the rules. Let's be idealistic for a second... isn't it refreshing?
So let me rephrase my previous post in plain language: to say "just take your business elsewhere" is naive and oversimplifying. The public's interests can only be served by a combination of educated consumption (voting with our feet), consumer advocacy, and political awareness as well as activism.