It is an assertion that there isn't a unique global maximum for all needs, as slight variations in how important each part of the tradoff is for you will determ

It is an assertion that there isn't a unique global maximum for all needs, as slight variations in how important each part of the tradoff is for you will determine whether A or B is better; and the only reasonable answer to "what's the best X" is "it depends". However, I would also assert that for many somewhat mature technologies the value of determining the global maximum for your particular needs does not outweigh the effort required to do determine what it is - in general, a reasonable local maximum will be almost as good as the global maximum; you want satisficing instead of optimizing.