Searching for the theory of everything with string theory is as promising as searching for it by playing chess.
Both string theorists and chess players are extremely smart people. Chess players are impressive. So are string theorists. They have intelligence to spare. All of them talk about their intelligence like pistoleros talk about their guns. They are die-hard machos.
The only issue: their occupation does not help finding the theory of everything. Not at all. Being smart does not count in the search.