Ideologies don't die. Progressivism and conservatism are hear to stay forever.

[HisGrace]

Was feudalism here forever? Divine right? Communism?

I was gonna say, can somebody introduce me to a Medievalist who wants a hereditary absolute monarchy and thinks the modern world economy should be organized around lords and manors. 

Communists and enlightenment style classical liberals are also pretty much gone and have no impact on mass society.