Men's comparative advantage, throughout human history, has always been their physical strength. It was the one thing a man could count on to provide value to society. That is no longer the case in our modern economy. You need intelligence, emotional intellect, and analytical skills. All of which men and women are on an equal footing at. So when you remove the ability to generate a viable income through physical labor…
I think your analyisis is missing something more fundamental - men's fundamental biological advantage is higher risk-tolerance, physical strength was associated with surviving physical risk to a degree that it justified the higher calorie expanditure powerful muscles require. Even with a lot of mechanisation of heavy lifting, men would still be more willing to do anything dangerous because a kin group can afford to lose a few men. It seems less that modern society has a reduced need for physical strength than that it has a reduced need for individuals to take on personal risk - and in fact, the way that risk is largely spread out through society in the form of the social safety net, one might say it has not just a reduced need but a reduced tolerance for risky behaviour. Tough times for men indeed. The instinct to take risks for admiration from our social sphere runs very deep, and there are only so many intellectual or financial risks worth taking.