In the path towards becoming a specialist in any field, repetition does not guarantee that someone will become a specialist, however it is the prerequisite in becoming a specialist in any particular field.
When someone keeps repeating the same works over and over again, he/she will then only be able to glean all the tiny little things that need to be improved further, if he/she has the desire to keep improving his/her products/services. The feedback that he/she gathered daily will become his/her precious friend in pushing him/her to be the specialist in the field.
In preparing Rojak day in and day out, we will then be able to find out all the smallest thing that could potentially improve further, and producing Rojak better day by day, and hence becomes a Rojak specialist.
How well and professional a person can handle all the little small things is the key in differentiating between a generalist and a specialist.