The best analogy is with general athletic ability. Yes of course, athletic ability is a multi-faceted thing; yes you can be good in different ways; yes, being the very best as baseball does not make the you very best at football; etc. Nonetheless, athletic-ness is a robust, real concept, which is very heritable, predictive of athletic success. Importantly, it encodes the empirical fact that if you are good at X compared to the general population, you are more likely to be good at Y, where X and Y can be almost any athletic activity.