Any form of communication can be helpful with norms and proper framing. I regularly use Slack for asynchronous decision-making where we’re explicitly not trying to fill each others’ calendars with more meetings, and we start with a specific question as a frame and what we want to get out of it. Threads can be long, but it also doesn’t pollute the rest of the channel, so it’s opt-in. It’s expected folks will bring the group back to the topic of discussion strays. And 80-90% of the time, we can get most or all decisions out of the way, such that if we have a meeting, we’re focusing that time just on the areas where a meeting is necessary.

Without some kind of guard rails through norms or framing, any communication, including a meeting, can get unproductive fast.

It heavily depends on why the thread is getting long.

If people are talking past each other on trivial matters, sure a call should be faster. Or if the core issue is to take a simple decision or iron internal politics.

If it’s a complex issue that needs input from a number of people, with resources and/or documentation to consult, and a need for well thought input vs. random babbling, participants should actively fight the urge to move to a call IMO.