Why do we do it? What drives us to spend the money we do on collecting toys?
If you look at the demographics of who collects it boils down to middle aged men who want to reconnect to their childhoods. There are of course much more to it than that, but if you look at the largest portion of collectors that's what it boils down to. As a middle aged man myself I grew up in a time that was right before and during the advent of electronics that have changed childhood forever. The days of getting out your figures and ships and playing Star Wars guys has now been replaced with going online and becoming Darth Vader in a first player game where you become the character. Phones, video games, Ipads ect are great and we have advanced as a society but I can't help but think of how much enjoyment I got as a kid by spending hours playing by myself or with friends. These times are special to us, they are the days we wish we could go back to if not just when we go into our cave and look at the elaborate displays we have build to our childhood mementos.
Some of us collect because of our love for the movies and characters, others collect for the investment of it. Before Disney bought the franchise and after the awful prequel movies there was a time when I thought the franchise might die off and eventually ride off into the sunset which would make us the last generation to put the value of these toys to the level we have. However, I believe our investments are safe for generations to come. The more Disney puts out content via movies, tv shows, theme parks, toys and memorabilia the more it secures the value of the original toys. The newer merchandise will never achieve the value of vintage but we can thank it for keeping it in the mainstream and continue to bring in a newer generation that will eventually see what we had as kids and want it for themselves.
So when your wife tells you that what you are buying is dumb and immature she is partially correct but the emotional happiness and the long term value makes it an investment worth pursuing.