> And the network effects can only happen because there is a tight coupling between the data (contained and scrambled within the HTML page) and the presentation. Had data and presentation be decoupled, I could have combined network information from various providers and present it to me in one overview.

I'm with you in principle. I think such a modular architecture based on standard interfaces between objects is exactly what we need, but I don't see how it precludes e.g. the dominance of Google. Google dominates because they have all the search data. People don't want non-Google results in their views. Non-Google results are worse.