Yes, this is the lesson from all of these discussions: once the obvious core functionality is taken care of, API design is becomes increasingly harder and involves iterating on interfaces and learning from mistakes… which is practically impossible or very, very difficult with Base (and the standard libraries), since once something end up there it has to be supported.
People mean well when they add new functionality into Base, but the bar should be much higher for that than it is currently. IMO politely redirecting all such additions to a package (if feasible) should be the default.