Excerpt from 'Why Aren't You a Better Guitarist?' by Tom Hess:
There is no such thing as musical skill. There exists only a large set of musical skills. Think about some of the very different types of skills a musician needs to have: a highly developed ear, good physical technique on his/her instrument, heightened creativity, the ability to improvise well, songwriting/composing skills, the ability to play in time, the ability to play with others, the comprehension of music theory, a good memory, the ability to read music, etc.
The list goes on and on. Some players have a natural ability to play fast, some have naturally good ears, some have good voices, some are naturally more creative than others, some are natural improvisers, etc. NOBODY has natural talent in all of the necessary areas to be a complete musician.