Final answer:
The prevalence of bell-shaped hats from the 1920s in today's boutiques represents the 'cycle of trends' in fashion, a recurrent theme where past styles become popular again.
Step-by-step explanation:
The recent abundance of bell-shaped hats from the 1920s in local boutiques illustrates the cycle of trends in fashion. This phenomenon is where past styles and trends re-emerge after a period of time. In the 1920s, fashion trends were characterized by simpler and more practical attire partly due to wartime metal shortages prompting women to abandon corsets. Popularized by the flapper movement, which featured straight lines and shorter hair, the flapper's gown minimized the female form contrary to the earlier Gibson Girl silhouette. The way these historical fashion trends return echoes the transformation in consumption patterns initiated by the advent of department stores in the previous century, which shifted buying habits from necessities to luxuries and standardized consumer goods.