That's a straw man if I ever saw one. No one here claims to be great. And no one is calling this product clueless. In fact all the discourse thus far is fairly civil other than this comment which comes off as hostile.
There will always be doubters, that doesn't make them haters. Why would they hate anyway? Shunning them as clueless and ignorant won't convert them--they'll only dislike you more for labelling them as such.
On topic, changing the subject is a means to accomplishing thread splitting and people do it for that reason. It may not work for everyone but it does indeed work and works reasonably well. There is nothing self-aggrandising about that.
Can somebody (who won't presuppose my motivation or my opinion) answer my question?
1) You send an email bcc'ing a bunch of people. Those people start responding, Gmail threads it into 1 thread. Sometimes you want this and sometimes you don't
2) The topic of a thread changes and you want to split the thread into two logical threads.
(One possible solution is editing the formail.php to hnge the emails subjects and make them different, for example add the submitter name, the submission hour. Last time, I just added a random number, it's slightly confusing but it solves the problem.)