Measurements matter. Two factors. You usually need to combine them with perceptive listening. Subjective feeds objective and vice versa.
But some measurements matter more than others in the hands of an experienced designer. One who measures and listens. My late friend Murray Zeligman modified cheap Grado cartridges in the 1970s. And he measured AND he listened. I once saw him look at a frequency curve , square wave and separation curve for a cartridge without knowing what it was. I still recall him saying he wanted the cartridge; he knew what it sounded like. It was an EPC 205 MK4 cartridge. We bought them. He was right. And it wasn't just luck. I saw him do similar things.
But this was particular cases. He never claimed he could do it all the time. But he sure was good some of the time.