But MMO's take significantly longer, require more people, and cost a lot longer, so in the short run MMO's is a bad idea and most not in SE's position probably wouldn't go that route. But SE is most likely looking for in the long term solution of profits after 5yrs.
All I really see is that they're doing so bad they need 3 MMO's just to stay stable. But a lot of companies do multiple MMO's so im not too surprised by this, look at perfect world or ncsoft, all have multiple mmos, though non really next gen as of yet.