I have noticed that there are people who either purposefully, or unconsciously, do not use threads. They litter the stream by making sentences instead of paragraphs. What I don't understand is how could Slack not see this as an issue?
From my individual's perspective, I don't get the idea of chats as a one liner when topics should be contextualized via threads.
Whereas I used threads all the time in Zulip, they are really not great in Slack, and mostly just useful for reducing noise for off-topic discussion.
Similar issues exist in email communications. I feel like these are really more just issues with the person's ability to communicate. Perhaps the technology can help, but I'm having trouble imagining how.
Unfortunately, I've tried to educate some of these types of users that I know (e.g., showing them that Slack's formatting options exist, are easy to use, stop quotes from randomly getting turned into smart quotes), but IME communications skills are one of the last things people are willing to accept feedback on. I find it often just gets acknowledged "oh, that's great, thanks!" and then promptly ignored (no change in behavior).
You may find this old conversation amusing: