There's no requirement for every/most/any threads to house lengthy discussions, since there's no provable correlation between number of replies and goodness/quality (see: the average imageboard general and sticky). Good/quality threads can (and often do) have little-to-no replies, and bad/crappy threads can (and often do) have many replies

I'd even argue that a higher percentage of Off-Topic@Heyuri threads with lengthy "discussions" inspire less OC and are teh sux0rz compared to our traditional, Heyuri-core, "spontaneously-posted image with a couple of quick reactions/comments before everyone moves on" threads