Whether a philosophy or methodology is "outmoded" is not a good indicator of whether it is useful, right, or pracitcal. For example, saving money and buying only what you can afford is technically an "outmoded" philosophy---yet it's value is evidenced in the lives of those who practice it.
Therefore the answers to this question must be based purely on personal opinion. Many good personal and social philosophies (along with some bad ones) have passed into history and become "outmoded." This is a shame because our society has left behind many of the ideas and principles that at one time made America strong.
Therefore it's logical to conclude that some people are "highly attached" to outmoded philosophies because SOME of these philosophies are highly beneficial to society and good for the individual.