Did they really have the potential to go further though? I mean from the sounds of it they didn't have the drive to go on. Knowing nothing of the band's members I can only think it would be of a lack of songwriting (not being able to write more than two new tracks they were proud of) or members pulling away from each other.
Either way this just sounds like not being able (/lacking ability?) to create a sophomore album... which I guess isn't all too uncommon anymore.
I do think they had the potential to go further, based on the two new songs. They may have had internal differences or just not been into their own music anymore, but based on what they were able to pull off with two songs, a whole album would have been cool.