Funny, I always though redefining traditional principles which are "inconvenient" was the quintessential trait of a liberal. I guess I've got all those gop evangelicals all wrong...
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.