Having been an editor for years, believe me when I say that no one will think twice about editing Brin's page to include some negative details, especially if they're well-supported. The Foundation itself has almost no editorial oversight over content on WP. Even Jimbo was basically booted from the BDFL role after a few controversial actions, and now has rescinded most of his privileges.

If there's anything Wikipedians excel at, it's causing a big furious stink whenever there's some indication of content tampering on the part of the Foundation. This is much easier to do when the vast majority of donors don't have a Wikipedia article on them, than when there is a list of 50 or so companies contributing advertising dollars.

The present system works. The banners get annoying, but the content is free from the taint of bought influence.