When the DC came out how many kids that had game consoles do you know had a playstation. Lets just say 5 out of 10. Now how many had a n64, lets says 2 out of ten. The rest may have had other systems, maybe one had a dream cast. My point? Its not a common system and its very easy to play backups on it. So there are few people that would try to make an emulator.
Now you are also way wrong on your analysis. Demul, NullDC, makaron and crankast all work quite well. Some preform better in certain areas then others. So I don't know what you are asking?
NullDC is by far the fastest, but any of the others play full speeds on the sandy ivy bridge systems. What are you working with a slow core duo or something ?