Traditional principles get re-defined all the time. The last time was post WWII when the nuclear family rose to prominance. Prior to that, multi-generational extended families were very, very common.
Folks have made the argument that one contributor to the high divorce rate has been the demise of the multi-generational extended family. After all, a husband is less likely to stray if he think his mother-in-law is going to be the one cleaning the lipstick out of his jockey shorts.
The point I'm making is that nothing in this world is static -- everything is subject to change and the influence of technology, economics, politics, and the television show The Family Guy.
No, they don't. The principles remain the same, even though the context is ever shifting.
My wife has a quaint way of putting it: the only difference between us and them is indoor toilets...