I don't think that women doing hard physical labour is a consequence of " female gender expression" under certain circumstances. If you need to do physical labour to survive, you do physical labour to survive and gender has nothing to do with it.

As to feminization of men, it's a popular topic (google it up), usually in the context of political correctness / rise of feminism / anti-discrimination policies / SJWs / etc. in the first world countries.

By the way, for feminization you don't need estrogen to go up, all you need is testosterone to go down. And, hey, look, testosterone seems to be decreasing in late XX century...