What competitors? They are only competing with each other. RIM and Microsoft are not competition at this point. Apple and Google teaming up on this is actually the best possible thing that can happen.
Let me put this in historical terms:
It's kind of like the earliest treaties between the USSR and USA regarding nuclear weapons. Sure, China/England/France had some nukes, but either superpower could have swatted those three down without an issue. Those early treaties weren't very substantial, and covered very few weapon systems. Yet they laid the groundwork for future cooperation, and eventual de-fusing of the Cold War.
Frankly, the more cross-licensing the better. It's our only hope until someone finally wises up and ends patents entirely. Had the patent system worked out like nuclear weapons (preventing global-scale wars due to MADD, or in this case, massive litigation resulting in sales bans), then I would be in favor of simple patent reform. Unfortunately, it's been shown that corporations can't be trusted to act in the best interests of consumers, the economy, or themselves when it comes to patents.