String theory is the butt of many jokes among some physicists. It's unanimously seen as a beautiful theory, but theory is nothing without experimental verification, which is of ultimate importance in physics. Even a string theorist would tell you that.
The physics principles that are most rigid are the ones that have proven most effective. At the end of the day, they're all just models. They are not meant to be "real" or "true". If the 4D black hole model makes original predictions that are verified by experiment, then it will become the mainstream theory. Otherwise, what is the point? There are an infinite number of potential models that are beautiful and elegant and could be used to describe reality. There has to be some criteria for which model we agree on, and that criteria is predictive ability.