Drip feeding contents only makes the announcement page look more 'active'. It may look fine to outsiders cause it might make them think "oh the dev care about this game regularly". It also funnels more players into whichever content they decide to release at XYZ schedules, thus masking these players from thinking how empty to places of activities are compared to the barren plains just outside the settlements 100y away. At least on paper, that is.
Of course, dropping us all the content at 7.1 wouldn't fix the lull that follows after either. At the end of the day their decision to drip feed us the content feels like one of those "all flashes no substances"-kind of decision.