I appear out of the mists of obscurity to share a link to this article. It has no direct references to RPGs, nor does it include anything potentially gameable; it's about how mustard went from one variety to several, and explains why ketchup is having trouble doing the same. Mustard, it seems, as well as most other things like coffee and spaghetti sauce, can be sorted into several "market segments", or personal preferences, if you prefer. Ketchup, on the other hand, has been perfectly blended to have universal appeal; creating different varieties, so far, has only resulted in tastes that tilt too far in one direction or the other.
The question I have that ties this all back to RPGs is: is D&D mustard, or ketchup?