I think there are several contributing factors for the show closing.
As mentioned before, the marketing for this show was abissmal. They could have really marketed it aggresively to mothers, daughters and sisters. I don't remember who said this earlier, but it does seem that the show just rolled over and died months ago.
I don't live in NY and did not get the chance to see this show (grr) but from the cast recording, the score sounds very weak. Too much time was spent on the operatic tragedies and they got old and boring very quickly. There are moments in the score that are very good (Astonishing, Days of Plenty)which makes me think that there was definitely potential for something much, much better.
I also think that there could have been more character development for all of the character's except Jo. Beth's death could have been a really touching and sad moment, but I found myself not caring because I didn't get to know Beth at all. I didn't really care about any of the characters because they were written as filler.
However, although this is by far, not the best show, I would have seen it if I lived in NY because I think Sutton Foster is incredible. Sutton is a big draw, but only to those who follow Broadway and let's be honest the number of people that follow Broadway are few. The tourists that go to see a show want to see a show they have heard about like Phantom, Mama Mia, Lion King, Spamalot, etc. I don't think Little Women had strong enough buzz.
I am looking forward to the cast's next projects and I know we will see them all again soon.
"When you're a Jet, / You're a Jet all the way, / From your first pirouette / To your last grand jete." --Brian Kaman