I think you're probably right. I haven't thought about what kind of metric to look at, but it should be pretty easy to at least get close to where the interesting conversation started.

Undisciplined

Stacker Saloon

saloon

If there's a high-value embedded comment lower in the subtree, it would hopefully have been zapped appropriately, though, right?  And practically speaking, it's not usually that onerous to read a subtree.  It's rare for them to cross the "see more replies" boundary, empirically.  Or at least, that's my sense.