Now my experience has been this. Like women who love their handbags, guys love their sneakers. You can look at it from two angles.
1) Just to have it and say that you have it and never wear them because they are collector's items.
2) This is someone's passion.
Some people just like what they like. Some people love what they love.
Want a glimpse of what some people are buying and selling sneaker-wise? Here's a first http://ebay.to/2atZseW