That's because they actually show interest in those categories. I don't see a lot of it in this one though and even if some people do, they probably would lose it in a few weeks or days.
Well ... all signs and Mariocam-RTA pose unique routing and movement challenges.
For your category idea it is:
- Start like you would a normal 16 Star run
- do a basement RTA for 70 Stars plus one extra
- finish like you would a normal 16 Star run
So please understand that there are reasons people are interested in above mentioned categories but not yours.
Noone will prevent you from running whatever selfimagined categories you like, though, and IF by doing that you can form a community that wants this to be a thing, come back and post your idea again, but please in the "category extensions" forum, where this would belong, if possible with a video of an example run.
I apologize for your last point, I haven't realized that there is an extra forum for category extensions
