I don't get why many more FREDS aren't offered.

I think they did not sell well because they were still on a gas chassis so the ride was not as good as a DP. They cost $8000 more. The HP was the same as the 8.1 workhorse on a heavier chassis so not a improvement in performance. The only advantage that I see was the improved fuel economy which was suppose to be 70% better which would be 13 mpg. I don't think many people got that much. But even if they did they would save about $750 in fuel per year if they drove an average of 5000 miles per year.