The large companies seem to be constantly in patent battles, often with each other, both as plaintiffs and as defendants. They win some and lose some. Since this is unproductive activity, due to lawyer bills and the diversion of attention from their core businesses, it simply must be a net loss for those players.

Why don't they call each other up, declare a truce, and cooperate in lobbying Congress to fix (i.e. largely repeal) patent law?