In simplest terms, the AMD & Intel perpetual license goes all the way back to the early 80s and Intel has tried to legally harangue their way out of it ever since, with limited success.
Not really. Intel hasn't shown any legal or business moves to try to cancel it ever since they developed EM64T and integrated it in their entire product line. AMD existing protects them from antitrust considerations. They would just prefer AMD stay in the budget realm so they can continue selling high margin products (enthusiast, laptop and server chips) without competition.
Not that they would complain if AMD lost their license or ceased existing, they just don't seem to actively be trying to cancel the license at this point.
