I don't really know what a "REAL" fan is. There are different levels and types of fans for every team. Dedicated, low standard, high standard, casual, people that dress in barrel's and Cowboy/Indian uniforms. I don't really think there is a right way but I will say that fans of the teams you spoke of that did expect to win, go to the championship or Super bowl are dead now. It has been so long for some of them.
Their latest fans are just used to getting happy with winning "Regular season" games, sometimes.
The fact of the matter is that most of us who gripe about not having playoff success now are ones that saw it literally ALL THE TIME when we were younger. It was more of a shock to not get to the NFC championship game. Now, younger people are out of their minds happy winning 9 or 10 games. Getting bounced from the playoffs is like "mehh, oh well it was a great year".