I have found that most of the single objective metaheuristic algorithms perform quick better than that of the traditional GA, EA, PSO, and so on.
But when they were improved with archive-method, decomposition-method, or indicator-method ways, the revised algorithm solved the multiple objective benchmark functions quick worse than that of the NSGA-II, NSGA-III, MOPSO, SPEA2, and so on.
Why?