With generalized polymorphic inline caches (dispatch chains) you get that cost down to the dynamic check and the JIT compiler can remove all reflective overhead.
So, in the end, you get a powerful MOP without reflective overhead.
So, in the end, you get a powerful MOP without reflective overhead.
...which results in a scenario no different in terms of overhead or expressiveness, than you'd have with a static MOP with runtime dispatch.
And, what do you mean with runtime dispatch? Static and runtime dispatch combined? I am not sure I really know what you got in mind.
With dispatch chains, the runtime dispatch is resolved at runtime and the JIT compiler can inline through it. But, you need that runtime information. A static compiler, like for OpenC++ can't usually do that.