 This shift, and their focus on the middle-class family eventually led to the first phase of La Onda, in which the children and grandchildren of the Revolutionaries began to challenge authority and individualizing and expressing themselves through rock and roll music and foreign fashion trends.By the 1960s, the import-substitution model was no longer working.The enthusiasm with which the Mexican government had fostering towards economic growth and political stability was slowly stifling the Mexican people.