my first thought has to do with the following:
I think things that are obvious to regular users of this forum (or any Discourse forum) maybe seem very intuitive or obvious but to a new user may not be so obvious.
Considering the four types of users above who may use the Support category, the first two are people seeking answers to a problem or exploring features for a possible solution to their community needs.
Of this group of users, some maybe just starting out, some may know their way around a little but still getting started and some may be Discourse power users researching advanced configurations.
That first group, folks who have never seen Discourse or are just starting to learn, may have no idea what a solved button is, what it’s purpose is or why it matters if they click it or not.
Some maybe desperate to solve one particular problem and once solved, never return to the forum. Are these user’s topic a waste of time? No, because they represent pain points that could make or break the decision as to whether to use Discourse or abandon it.