Why not just have a single thread and let everyone ask questions there?
This is an approach pioneered by Sephora (3000+ responses to this thread and counting).
If the top contributors want to easily find unanswered questions to answer, do they want to wade to the end of 3k+ responses?
It’s hard to merge common discussions into a single, definitive, thread you can regularly update as new information comes to light.
If management want reports on which topics are most popular, which problems are most pressing, what terminology people are using, it becomes far harder to pull this data from 3k+ responses.
Reducing the number of threads is rarely the real problem. The real problem is developing a workflow that will efficiently let you respond to each question, update old questions with new information, merge similar questions, and gather insights from these questions. Focus on that.