Lacking a rigorous and universal definition of what happiness is, all this talk is pretty much pointless. Maybe the whole feminist movement fed women with unrealistic expectations and their misery stems from the reality-expectation mismatch. Anyways, who cares?
The authors of the above paper seem to have used different operational definitions, and they all point in the same direction. So one can state with reasonable certainty that women's happiness declined in the last 30 years.
A discussion about potential explanations for the phenomenon can hardly be called pointless.
[1] http://en.wikipedia.org/wiki/Operational [2] http://en.wikipedia.org/wiki/Construct_(philosophy_of_scienc...