We know, also on Bitcointalk, coders are active because Bitcoin is a very technical subject.
When normal people ask a question here, coders will look at it and reply.
It’s a very good feature of Bitcointalk because coders are still here.
Firstly, one does not need to be a coder to understand the technicalities of bitcoin. Someone that has no knowledge of coding or programming can understand bitcoin technicals very well and answer bitcoin questions. I doubt that all the people providing answers to bitcoin technical questions dwell in the back-end of bitcoin.
Again, not everyone that understands codes and that codes knows bitcoin. You can be a coder and knows nothing about Bitcoin or blockchain coding.
So, you can rephrase your question by asking how many blockchain developers are here in bitcointalk.