In your original post, however, you state (my emphasis in bold):
These conclusions derive from counting the posts/views in each thread. But, given RMwebbers' propensity to go off-topic, this may be little more than a 'never mind the quality, feel the weight' approach.
I'm not sure exactly what you mean by "big steam", presumably large steam locos, as opposed to Terriers etc. But I don't think it fair to conclude that there's little interest in "big steam" in this case. Note that each of these threads is not just about big steam, but a specific prototype. So, the overall interest in big steam within the Hornby 2021 announcements would be the sum of these threads. Comparing the DE (many models) and the 9F (one model) threads doesn't reflect a relative disinterest in big steam, at least not as it applies to Riddles' big boy.
I can't readily access the DE, P2, or A1/A3 threads, since they were of so little interest to me that I have them hidden (too many pinned threads in this subforum, I had to cull some to allow room for new/current discussions on the first page).