[zyxley]

Would couldn't they? They do business across most of the world already. Think about how many countries have people with WoW subscriptions.

Heck, just take a look at their list of offices: http://www.activisionblizzard.com/locations

[Kiro]

Because US law doesn't apply to other countries.

[zyxley]

Most countries have something approximately similar to the broad strokes of US copyright and trademark laws. Details are different, but "just using the same assets and names directly" is going to be a problem in pretty much any jurisdiction with enforced rule of law.

[Tomte]

Just about every country in the world recognizes some form and variation of copyright and trademarks.

You do know that, right?