I wish, and we've debated this. There is some caching taking place because some of these summary pages (/forums, /active, etc.) are heavy on the db, so we have a bit of data in memory. Dumping cache and reloading is heavyweight, and because we get hit by spam bots at times with 100s of posts, we might kill the db.
This is worth revisiting, and thanks for the note. I have a couple other nagging items in progress that I'd like to get fixed first, but then this might be something to look at.