Skill isn't just learning how to use an instrument, it's the meta-knowledge, the creativity and the feel in intuitively knowing when to use a certain feature or command.
It's when you instinctively know what is the right thing to do or to say or to where to move or who to talk to or what you must do.
In music, learning just the chords of a guitar and what notes each string plays when plucked doesn't make you skilled.
In IT for example, a lot of "programmers" call themselves programmers just because they know what commands do what in a programming language or operating system. But a skilled programmer is one who knows how to blend them all in to create a work of art.
In management, just because you know what privileges and power a manager can do doesn't make you a manager. It's when you know what to do and when to do it that makes you a manager.