No, it means you've not at all read the paper you are citing. I am summarising that paper: they note a decline in *subjective* happiness that is contradicted by other statistics (like suicide) and by other subjective findings.
They then discuss 4 reasons why the drop might be happening. None of those reasons, or anything I wrote, imply what you have written in this post. I do not know where you are getting that from. I know most of us are posting in a football forum and including myself, often don't fully read what we are citing, but I don't think you'v ever opened that paper, nor have you even read my short post...amazing.
About the hypothesis that being part of the workforce is the cause of this decline: I think
@Silva nailed it. There was only a short period in history when significant numbers of women were not working. That refers to a number of wives of financially comfortable men in the west during the late 19th and early-mid 20th century.
In feudalism, women were part of the peasantry and also did (very hard - no machines at all!) household labour. This continues in most 3rd world countries where poor women farmers have to at the very least walk miles to get water and wood and cook for their family, and usually have to do lot of work in the fields as well. During industrialisation, women joined the industrial labour force in large numbers, as can be seen from
this in the US and
this report from Manchester, both 19th century.
The overall default state for women over millenia has been (very hard) work. The exceptions were feudal queens and wives of nobels earlier, with industrialisation this expanded to wives of industrialists, and finally to the wives of upper(?) middle class men. For various reasons (second-wave feminism, declining real wages) this process stopped, and reversed, in the west.
So it would seem dubious to me that entering the workforce has caused some evolutionary switch to go off and make women unhappy.