The detailed development, implementation, and operation of a design usually represents a significant investment. This makes it a good idea to first explore a number of possible approaches before committing to a single concept.
But concept selection is a strategic choice. The decision comes down to a judgement of which concept looks most promising, not to a determination of which one is certain to have the best possible performance. And at the end of a completed design project, you can never be certain that a choice to go with a different concept would not, in fact, have led to a better outcome. It is just that at the time, this concept looked best, and that therefore it was the one selected for further investment of development resources. Who knows what would have happened if those same resources had been invested into a different concept?