As video moves from TV to the internet it is silly to think that any one website can handle all the content, even if that one website is owned by Google. On TV there is not one channel for every show; there are many channels that focus on certain types of shows. The internet should be the same. There should be many websites that focus on specific types of shows, and there should be one directory that lists all these websites.
This is just a fringe thought, but imagine if a company builds an application that lets all the major media companies have their own website, where they can show whatever shows they want. And all this application does is tie all the video websites together.
Kind of like how Yahoo listed all the cool websites, this application could list all the cool video websites [in an interactive way].
Your theory is not entirely out of the question even if the above is true. Google may have acknowledged this. I say this because they have said that youtube will remain youtube while Google video will be a site to organize the content.
Most major networks do have applications online to view their content.