Personally, and this is only my opinion, but I think it just isn't society that adds to the pressure of what people think each role should be. I think people add to it as well through their own misunderstanding or interpertation of the Bible.
I attend a Baptist church and we are free to interperate scripture our own way as long as we keep the basic core beliefs. This is both a positive and a negative. The negative being that people interperate what part of scripture they want, don't bother to learn the rest, and then declare that they know all. An example of this would be a man who takes the scripture from Paul and Proverbs 31:10 -31 (Perfect Wife scripture) and expects a perfect wife. Most men that I know who have done this are either not truly the head of their households or they act like they are in some fashion but treat the wife as a doormat and entirely sweep over the "as Christ loves the church" part for their own personal reasons. Personally that is not a true believer but rather someone looking for a reason to have their bad behavior condoned. Sorry... *pushes my soap box back to the corner*
Anyhow... I think it is a combination of society but also a combination of what each person is willing/wants to believe. As some one once told me, it is always easier to be a Christian at church.
On a seperate note though... there are at least a dozen examples of married couples, in all age ranges, at my church, that to me display the how the true nature of Paul's writtings are to be done. The wife is a vital part of the family and is just as important as anyone else. But, they also have a sense of peace that I truly believes comes from the fact that their husbands are being Biblical husbands. I honestly don't believe that any of those relationships are D/s... but the way they function and the harmony between the couple and the family unit in general is just awe inspiring to me....
Sorry... just rambling now! Great thread... thanks for starting it!