Market Position Archetype?

The position chart is ubiquitous. A set of X and Y axes representing 2 dimensions in the market and dots representing company's positions with respect to those dimensions. There are many versions. Price v. Quality. Capabilities v. Price. Price v. Value. Luxury v. Reliability. Price v. Economy. These are all interesting and useful, but why are there 2 and only 2 axes? No doubt, having two axes makes things more interesting than one. Having 2 suggests the possibility of trading-off one dimension against the other. For example, it's easy to be high in both price and quality. But, it's hard to be high in quality and low in price. If that's the case, then why are there no 3-dimensional maps? Maybe the famous price, quality, duration triad would work here? I think the reason for constant 2-D thinking here is something in the human mind. We tend to think of products, companies, etc. as "a and b" or "a and not b". We just naturally use a pair of terms to describe everything. It's all we really need to position things in our universe of meaning. Take people. We will say, "he's attractive and nice". That positions him very effectively. Going on with more attributes (more dimensions in the graph) is interesting, but it's not necessary for the positioning. So, my conclusion is that every positioning statement should be in the form of "a and b" or "a and not b". This is how we human like to see the world.