Possible reasons for low question rate
This is just trying to limn the problem. No judgment or conclusion is intended, I am just outlining possibilities.
Most of the possible on-topic questions that can be asked have been asked
- Requests for recommendations
- Questions on complex topics are too broad
- Questions that elicit opinion-based answers
- Identifying a style/genre, instrument/equipment, technique, chord progression
- Questions with too many possible answers or that would require an extremely long answer
It may be that the bulk of questions musicians have relate to off-topic questions. Questions that are on-topic may be difficult to craft for new users and most possible on-topic questions have been asked so the question rate is low. I'm not suggesting we change the policy, I'm simply making an observation. We may just be stuck with that.
This SE isn't well-represented in searches
This might be because searches for particular questions don't match our questions for some reason. Or it might be because our questions don't have enough links from other sites.
This SE isn't viewed as welcoming
This is a hot button, I know, but I just have to put it out there. If this is the case then it might be for a number of reasons, many of which were outlined in https://stackoverflow.blog/2018/04/26/stack-overflow-isnt-very-welcoming-its-time-for-that-to-change
The thing we don't see yet
Maybe StackExchange Data Explorer (SEDE) can tell us something. Or you?