Wikipedia:

Before his accession to the throne, he served as heir apparent and held the title of Prince of Wales for longer than any of his predecessors. During the long reign of his mother, Queen Victoria, he was largely excluded from political power and came to personify the fashionable, leisured elite.

The banality of the King Edward ad campaign was typical for the time; "Happiness is . . ." was one of those set-ups for Peanuts cartoons or greeting-card sentiments. The smiley-face was just beginning its reign of terror.