Imagine a dinner conversation at a dinner table with, say, 6 - 10 people.
In a normal dinner table conversation, after a lull when someone stops talking, the next person who talks is very likely to be responding to or continuing a thought from the last person who talked. That’s just how conversation works. If people want to split off from the dinner table and join (or start) an alternate, radically different conversation at another table, that’s also possible.
There’s rarely the need to say “I’d like to respond to something Scott just said”, because in a normal dinner table conversation with a group of people, it’s always implicit and assumed that the next person who talks is picking up what the last person said and running with it – unless they specifically say otherwise. Or, y’know, get up and leave the table.
I would argue that this is completely normal and natural.
We’ve tried it both ways, and it is so common for the last person to reply to something that was just said that with all the obvious repeated metadata of “as Sally just said…” on every reply, the conversation quickly becomes extremely, onerously noisy.
(bear in mind this indicator is only suppressed in a very narrow set of conditions: when there is a a) one and exactly, only one reply b) it is directly under the post it is replying to, and c) there is no blockquoting of the post.)
I do think that clever-for-the-sake-of-cleverness one sentence quips and retorts and bon mots are far more strongly encouraged in threaded systems, whereas they aren’t here. You might even say they’re discouraged in Discourse. In all honesty, I would be lying if I said that wasn’t kinda by design.