im not sure what you mean - bigger companies also use the slack maximalist approach.

I’m not just talking about heavy use of slack, I’m talking about maximalism as described in the article. Larger organizations will typically have several different systems to perform many of the functions described in the article, and it generally wouldn’t make sense to replicate that functionality, but worse, in slack. It would quickly become unmanageable, because slack simply isn’t designed for that. Heck, slack is barely designed for its own core functionality - e.g. its thread support is incredibly limited.