I have quite a bit of money tied up in pins. But over the years, I have not lost anything. I've lost a few bucks on games, and I've made a few bucks on games. I've put too much money into a restoration of a game I loved, and I've bought cheap games that were amazingly fun.
Overall this is why I've never let a couple hundred dollars stand between me and a game. I'm not going to get ripped off and pay a huge premium, but if I'm close to the sellers price, I'll have the game.
I think if I sold them all right now, I'd end up a bit above, or at worst even. There is an opportunity cost, where that money might have earned me more money if it had been sitting elsewhere, but really, not much. And I've owned a bunch of pins and had a blast with them. So I win.
I can't name a single other hobby I've done that I was able to get all my money back in the end.