In 1918, Hermann Muller explained how evolution enabled systems of “interlocking complexity” to develop, largely by protein modification. The systems would start out being simple and not irreducible, then would garner links or steps over time and gradually change to become more interdependent, until they could no longer operate independently. That, of course, is the Intelligent Design state of irreducible complexity.
Muller gave real-world examples of systems in various stages of transition.
So the great conundrum of IC was solved 89 years ago!
Hermann Muller went on to win the 1946 Nobel Prize in medicine for his work in genetics and mutation.