It's really nice to point to things like the Cluetrain Manifesto and tell companies that they should implement these kind of ideas if they want to succeed on the internet, but not only do you have to convince them that it would work, but they then have to actually implement them in a way that is not only true to the Manifesto, or whatever set of ideas you have, but also makes them money.
Huge corporations make a lot of money. They will always make a lot of money, whether or not they use the internet effectively. While it is true that the internet can make these companies more money, why risk the embarrassment of failing on the public stage if you can let someone else take the risk and still make money off it (think of the iphone and all the companies that are now making iphone clones).