Or you can just click on the link below:
While the threaded view of recent memory did have some quirks that almost certainly would have dissuaded those not familiar with it, those with the most impact were introduced relatively recently, which means they could have been corrected if anyone had bothered to do so. I suspect another reason for the lack of use is simply that many don't even know the threaded view exist -- an inevitable consequence of putting the setting inside a menu instead of using a readily visible icon as had been done in the past.
Granted, portions of the threaded display can become fairly useless when the tree gets beyond a certain depth; however, a mitigating factor is that this occurs most frequently in the light-hearted topics where one is less likely to be concerned with following a specific thread than in the serious topics.
Yes, it is true many other forums lack threaded views. A perfect opportunity to distinguish yourself among the crowd, especially since you already have the feature implemented! For whatever it's worth, the threaded view is perhaps the most significant reason I have 20K+ posts on CM and less than 100 on the Catholic Answers forum in the same span of time. (If it gets pulled tomorrow, y'all will know why! )