The thing is that women did work full time in the past. They worked in the fields, as maids, in factories... Only well off women were exclusively stay at home wives. Men expect both because it has been like that for centuries. And it was like that because women didn't have full rights. They weren't allowed to open bank accounts, work without the husband permision, etc. And the husband controlled all the money included the wive's wage and inheritance.

That is why we still have men who expect that, because they have grow up seeing that.

But of course you are right, is a terrible deal and women who aren't forced or brainwashed into that won't take it. It is as simple as that.