It's not a fear of change itself. It's a fear of ruining something great to appeal to a new fanbase who may not appreciate it anyway. Like George Lucas and his changes toStar Wars. He's not going to win any new audiences, he's just going to piss off people who already enjoyed the films for what they were.
I just think games in a series should evolve, not change. If you want to go in a new direction, make a new IP. That way you can attract new fans, keep the old ones, and possibly even please both with your shiny new game.
Example of change: Every Final Fantasy after 7 has been so wildly different, that the series barely has an identity anymore. Every game has folks who love it, and others who hate it. Never have I seen fans of a single franchise bicker so much over each game. Square is no longer selling the Final Fantasy games, they are selling random jrpgs that happen to be called Final Fantasy, and really the name is the only thing carrying these games lately.
Example of evolution: The Legend of Zelda has remained largely unchanged. It has gone 3d, expanded in size, acquired new tools and uses for old ones, shifted in art style, etc. but is basically the same game we fell in love with 25 years ago. Naturally there are people who don't necessarily hate the gameplay, but feel the series has gone stale. But there are plenty of games that offer Zelda gameplay in a non-Zelda setting and many of them did all right.
Saying people only hate games because they fear change and are blinded by nostalgia is the same kind of ignorant streotyping as saying people only hate games because they are popular. It's the oversimplification of an opinion used to dismiss it entirely. OP, how would you feel if I said you only like games to change because your ADD won't allow you to appreciate anything for more than 10 minutes? You would argue that my statement is full of assumptions, and is grossly oversimplified. That is my response to the topic question.