It reminds me of 'The Time Machine'

For those of you who haven't read the original story by H. G. Wells, you should. The protagonist travels to the distant future, and finds a race of childlike beings has evolved from modern man. As time goes on, the protagonist comes to realise that these are the descendents of the upper classes, with the descendents of the lower classes living below the surface and laboring to maintain the lifestyle of the upper classes.

While in Wells' tale, it simply suggests a continuing trend toward pedomorphism in humans, if we look at it from the point of view of a drug in the hands of only the upper classes...