^ I don't really think sales has anything to do with this, cause if so then melon would of disbanded like 3 years ago lol. Their stuff post H!P grad wasn't exactly mainstream so I don't think they were expecting high sales with their recent projects. What wouldn't surprise me is if we hear a marriage/pregnancy announcement from one of them soon
edit*
but speaking of sales their current album is actually doing quite well (for their standards lol)
-- -- -- -- -- --初39 メロン記念日 「MELON'S NOT DEAD」 and their second day they rose all the way to number 29. This announcement of their disbandment might help sales too...if they are able to stay within the top 50 then they will easily outsell their last couple H!P releases.