A lot of it is the collecting bug and the collecting community.
The collecting bug is about the chase, the want to get more and more interesting objects. In the community, people encourage each other in various ways. On the positive side, it feels nice to help others with the same interests. On the negative side (in a way), there are lots of stuff that I would not even have thought of acquiring if it hadn't been for the community driving up the interest.
I also have a collection of computer keyboards: Some vintage, some new, some I have built myself. I find that that community of keyboard nerds has many similarities than differences with the community here on the RPF, even though the objects that we collect/build/modify/customize are completely different. There are group buys of parts, research threads on vintage hardware, nostalgia, identification of objects in photos (...), long discussions about various topics in the larger world around the keyboards etc. And these collectors are certainly bitten by the collecting bug in the same way as here.
Also:
I love creating stuff, doing stuff with my hands, and learning new crafts and techniques.
I'm a nerd at heart, who loves to dwell deep into research about esoteric topics...
The foundation is of course my interest in movies. My interest in Star Wars props has been fed by being part of the larger Star Wars fan community.
I was introduced to movie magic by my dad who was a journalist who wrote mostly about movies, and had even worked in the industry.