A key concern of nearly all of Fitzgerald's fiction is the way in which the 1920's, or "The Roaring Twenties" as they came to be known, actually created many different problems through a variety of factors, but mostly because of the change in morals and the conspicuous consumption of wealth by the rich in an age of poverty for the rest of the nation. The Jazz Age, which is another name that has been given to this period, was a time in which the rich were able to live their lives seeking pleasure alone and as a result led shallow, superficial and apathetic lives. This is perfectly characterised by the lives of the Buchanans and Jordan Baker in The Great Gatsby.
However, according to the great quote you have identified, living life focused on such shallow and meaningless obejctives means that you are blind to the "redeeming things" of life, which are what emerges from the struggle of life. Living life without struggle means a lack of growth, maturity and development which is crucial for human happiness. Thus underneath the apparent veneer of hedonistic pleasure-seeking, Fitzgerald's fiction exposes the darker side of such life: the way that relationships and morals are impacted and the emptiness that leaves people void of purpose.