I guess the emphasis is on "defaults" because interruptions can be minimized by seeing notification levels and muting. Lack of structure? There are channels and threads, I'm not sure what else I'd need from a product like that. Retention is fixed by paying for it.
with slack, it's easy to have a thread with 15 different answers which are all slightly different.
The "knowledge retention" features I'm looking for is being able to mark a thread as "this is the decision made", have that highlighted in metadata and archival, maybe be able to link off to a notion page, and have the thread closed to finalize the decision.
EDIT: the number of times I've had to kick people off a thread because they're adding bad info during a crisis reallllly drives my desire for marking canonical messages lol
So let's applaud those who try, even if we believe they failed (or at least haven't succeeded yet).