That String Theory continues to adhere to known results keeps it in the candidate pool. If it can make the same predictions as the current framework, then it makes sense to keep working on both because neither has a known advantage over the other in predicting unknown phenomena. The only way to find out is to continue exploring all such theories. Since human talent and research is limited, it becomes an economic problem. Is it worth having half of the brain power working on two equally plausible theories? Who knows... but what I do know is that diversity in this field is creating new ideas and new mathematical tools and that has to count for something.