@Ash
If someone wanted to disrupt the theming industry built around wordpress all they would have to do is start giving away all the premium GPL themes on their site.

Ethical or not (and since its within the law for GPL …) people would line up to download the themes for free.

Currently there are dozens of sites doing this very same thing. The are also adulterating the original theme by adding encrypted spammy footer links. The unsuspecting users are turning to WordPress.org to find out how to remove the spammy links.

Regarding providing support for premium GPL themes, I don't really think there even needs to be a policy on this. Most volunteers like myself simply won't answer the questions. Why should they? What is the motivation for doing the work when they know someone else is making the profit?