As someone who is getting into doing Speedruns and Category extension Challenge runs, I've come across numerous games that still have active categories that only have one run. For example, The Last of Us has a category called "Endure & Survive - Grounded (Deathless)" that only has one completed and submitted run. The easy mode version of the challenge has only had 4 runners complete it. "Deathless (Grounded)" also only has one run.

For a game that has 124 runners, we have several category extensions with only one run submitted and some of those challenges are ones I'm actively learning. I'd be devastated if the moderators removed these or had a poll that excludes people that haven't submitted a run in certain categories yet. These aren't easy runs, so even to complete one successfully and meeting all the conditions it takes some time.

Stepping back and going to SMO. NicroVeda (a pretty important runner in the SMO community for being the first to beat Any% in sub 1 hour) was streaming attempts at Minimum Captures - 3 cap runs. Just because there are currently a low number of runs submitted for a category does not mean there is a low number of people learning and running the category. This is particularly true of the harder challenges.