The majority opinion relies on that in part too, briefly suggesting (in III-E) that it might not necessarily have reached the same decision if Patent Office inv

The majority opinion relies on that in part too, briefly suggesting (in III-E) that it might not necessarily have reached the same decision if Patent Office invalidations weren't appealable in the courts. They don't specifically say that appealability is required, but they leave open the question of whether this review system could be upheld without it.