Haven't seen a lot written on this. It's so true. I also agree competition can help you focus yourself. It can provide a valuable reference for drawing lines in the sand.

Above all, what always comforts me is knowing that most companies half-ass a lot of stuff or get screwed up in some way. Bill Gates remarked how refreshing Steve Jobs is as competition: at least he sticks around, unlike the hordes of competitors he's faced.

Companies that really are ready to fight to the death are extremely rare. If you're one of them it doesn't matter how smart or rich the competition is, they should be scared of you.