This is what I was getting at. If the course is designed to be 'fun' for only 30% of players and as such only 30% of players use the course, that's a shame and a bit of a waste when we could design differently and make the course work for ALL players.
You're also presumptuous in thinking that only the top 30% enjoy those tough courses.
There are many lower-rated players who enjoy the challenge of a gold course, or at least a blue course (target 950 rating). I routinely play a course that players from 850-1000 seem to love. On a bad day I've shot triple-digits on its 24-hole layout, and double-digits on a couple of individual holes.
The variety of courses---style and challenge---is one of the great pleasures of disc golf.