Somewhere along the line, IPB disabled the default status updates setting.  They just recently added a setting to allow you to enable the default setting, for new accounts.  How do I mass apply this to existing members?  I have new members groups with this "group level" setting turned off by default.  Regular members enabled.

You edit the group those people are in to add the "Can post status updates?" item near the bottom of the Social tab. You can also set a automatic group promotion criteria so new members move into the more full featured group after a certain amount of time, posts, etc.