My original point is that Lawful/Chaotic subjects should be just as easily determined as Good/Evil subjects, and as such, should be just as easily prepared against. The fact that they aren't changes the paradigm of power significantly between the four alignments (i.e. for optimizing and powergaming purposes, Good/Evil alignments suck unless you absolutely need them for something, such as being a Paladin). If you're simply a Lawful/Chaotic character, the likelihood for enemies to be using Axiomatic/Anarchic weapons, or Anti-Lawful/Anti-Chaotic spells against you, unless they too, are Chaotic/Lawful, respectively, are extremely reduced (and if you're True Neutral, you're basically immune to anything that requires specific Alignments, or you suffer the least effects, both benefits and penalties, of every Alignment-based effect).
I think this is by design. If the conflict between Law and Chaos were as important in the game as the conflict between Good and Evil, then it would be just as difficult to have parties with both Lawful and Chaotic party members as it would be to have Good and Evil party members, eliminating a source of interesting but usually not disruptive party disagreement.
And if you're going to have one axis being superior it makes sense for it to be G/E for the reasons other posters suggested - G/E is a bigger part of the larger culture than L/C, and L/C isn't all that well defined in any case (maybe a chicken and egg issue, but result is the same).
I actually redesigned my current setting to focus more on the Law/Chaos side. Archons and Devils now have DR/Chaotic, Demons and Azata have DR/Lawful, and there are some relatively easy physical markers. For example, in this setting, outsiders with both animal and humanoid parts are chaotic - azata and demons have feathered, batlike, or insectoid wings while wings of archons and devils are constructed of metal, light, shadow, flame etc. It's been interesting but more as a diversion. In fact I think it's trending in the general direction of LG vs CE as the party has been going out of their way to mediate disputes wherever possible in a way that gets the grudging respect of a lot of CG opponents.
I remember seeing a post by James Jacobs explaining that the L/C conflict was pretty significant on the outer planes but usually wasn't as relevant to mortals. Can't find it, though.