If everything else can be controlled, then virtual calls are being used unnecessarily. The fact that an indirect calling mechanism which has to first use indirection to retrieve the address to be called (and possibly do more work, like fixing up a pointer) is slower than a static call is completely unsurprising.

If virtual calls are used essentially, then it's a canoe-versus-bicycle comparison, because everything else cannot be controlled. The program based on static calls has to be written quite differently to solve the same problem, and the benchmark then measures the entire approach. Plus the benchmark doesn't account for benefits that it doesn't measure, like maintainability and extensibility of the code.