Allegory

There is a reason why it took big business so long to figure how to use the internet in a way that does not make them look foolish  (compare the sites here with their sites now). People are afraid to take risks. If we weren't, then everyone would be an avant-garde street artist. There is a reason that peer pressure is the focus of anti-drug and underage drinking campaigns. Not only do employees of companies have to overcome their own fears of failure, but then that have to convince their higher-ups that their crackpot idea is not actually a crackpot idea. And now the higher-up has to go to his own higher-up with the exact same idea and exact same goal. 

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).