Answer:
The author's main purpose for making a reference to the Beatles in this sentence is to emphasize that holly is a novice guitar player
Step-by-step explanation:
Holly feels frustrated since she has not learned how to play the guitar yet, she must have thought it was easier than it is, when her parents see that she is about to quit playing guitar they try to persuade her and the expression "no one's asking you to make records like the Beatles," coming from her father is to show her that she is just starting and that with practice she will make it.