That's a thought! Maybe you should give Witten, or Strominger, a pep-talk about the merits of the program. Say nothing is more fundamental that anything else so not to be disappointed if you don't find the ultimate reductionist theory of existence. Just kidding.
But empirically there does seem to be this loss of unification drive and direction that Suprised was discussing---this sense of "wrong turns". So I think it is worth thinking about what caused it. I'm thinking management--program guidance--vision. Maybe that's wrong. But there should be some explanation for it, and it may not be intrinsic to String per se.
You remember I listed Witten's "string" and "membrane" papers over the past sixteen years 1995-2010. Here are the same numbers for Strominger and Maldacena.
1995-1998 1999-2002 2003-2006 2007-2010
38 29 9 5
23 14 22 4
27 33 24 9
It looks like Witten shifted interest sooner than the other two. Here are the Spires links so you can make your own count if you like, using core string keywords "string model" and "membrane model". Just put in a different name instead of Witten and repeat the search.