"For now this will be a no-fix due to licensing issues. All libraries that we host on the Google AJAX Libraries API are offered free of charge with very liberal licenses. EXT, however, requires a fee for users wishing to use it commercially. We like to keep the libraries consistent so that we don't put our users in a dangerous situation where they might be liable without knowing it." (http://code.google.com/p/google-ajax-apis/issues/detail?id=50#c44)
What's interesting is that Extjs is available under GPL v3. A commercial option is available if you don't want to release your code under open source (http://extjs.com/products/license.php).
Clearly, Google can support whatever it wants, but from the viewpoint of at least one team at Google, GPL is not liberal enough to be considered true open source. "Open source" is when a commercial company can use code without a fee.