A job pays you for the role rather than what you can do!

From a book which I recently finished reading:

"A job pays you for what the role/designation does rather than for what you can do, which is why the compensation it pays doesn't justify your capabilities. Owning a business sets you free to use the full potential of all your abilities and interests."

Reference : Kanth Miriyala, Book : 'Entrepreneur 5pm to 9am', Preface