Unsung

Orbiter is still being developed, slowly, and also has tons of add-ons that enhance the game. Fun is relative, and there wouldn't be an Orbiter community if nobody enjoyed it. Orbiter is a much tougher simulation and takes a lot more effort to learn. Just successfully flying by a planet in Orbiter is a much greater feat than in KSP and can feel rewarding. KSP is not as niche as Orbiter so it can appeal to a wider group that cares less about accuracy. It would be a bad idea for KSP to limit its audience by trying to be a more realistic simulation.