Uh, no. This is where a good scientist keeps digging into it in order to expand our level of knowledge.
In which case your original premise that "causation is frequently so complex that it can not be deciphered with our current level of knowledge" is not correct. You cannot have it both ways: either the causation is understandable - with hard work and insight - or it is not. If it is understandable then this is what a scientist will go after because understanding is their goal. For a medical researcher establishing causation is enough which is very susceptible to random statistical flukes.