I'm not sure it's fair to characterize an older fan's apathy toward new stuff that way. I think once you are a fan of a certain vintage, you are no longer excited about new things simply because they are this year's model.
I love the mecha shows the way Shougo loves tokusatsu but I don't watch most new series in their entirety as they come out. I feel like most of what's been produced this decade was not very good for various reasons.
While a lot of my all-time favorites happen to be old, I don't like them because they're old. I like them because they were the cream of the various mecha show crops they came from. When a newer show like Gurren-Lagann is the cream of its crop, I tend to like that, too.