He was simplifying for clarify, but what he said was just another form of what the person above him said which was: >> no matter what problem you can think of,

He was simplifying for clarify, but what he said was just another form of what the person above him said which was: >> no matter what problem you can think of, either it has already been solved to the highest level of abstraction, or it's an unsolved and famous problem, or not worthwhile/trivial. << So, Millennium Prize is an unsolved and famous problem like Reimann Hypothesis, etc..