I would bet it's the marketing people who get in the way. They ask who the target audience is for a receiver without the amps, and see that they have more money to spend, or will see a higher perceived value, than those who just want an integrated unit. So that sets the price right there.
You are dead on about this one in that marketing in certain areas dictate what is sold. I can recall back in the late 80s and early 90s when Yamaha offered a complete line of audiophile separates in a champagne color that looked great and sounded terrific. Once surround sound took hold and everyone started to jump on the HT bandwagon, these beautiful separates started to disappear. Not only that but when they were still offering the champagne color in other parts of the world along with integrated amp surround sound processors(without the tuner), all you could get in North America were AVRs in any color you wanted as long as they were BLACK!
According to the mainstream companies(Onkyo/Integra being the exception), Pre-Pros are a "niche" product so the few that offer them end up putting in balanced outputs in the space occupied by the speaker connections and charge a premium to those that believe they are superior. I guess Emotiva and to a lesser extent Outlaw(when they finally get around to having one available)are exceptions to that rule.
