This may be a harder change to make, but I feel people in the forum respond more to the last post, as opposed to the actual thread topic. Once you get past the first page the thread topic doesn't even load when you view the thread.

While it is against the rules to go off topic, I think the software design actually encourages going off topic.

I'm pretty sure a lot of people reply to threads without even considering the topic, and the means discussion quickly deviates from its original intention. I'll try to follow up with potential actionable changes.

Yeah, if it is possible, always showing the opening post would be useful, especially if the thread creator updates it as discussion continues.

Exactly, just like the Steam forum. But I'm afraid that despite everything, people will go off-topic anyway, especially those who go against users' opinions. But surely always showing the first post at the top will reduce the problem.