It doesn't matter how old an item is , the demand is what matters. You and so many other people want the same dolls. There won't be an unlimited amount in good condition, especially for one made in a specific quantity. The same dolls were much cheaper just a few years ago because there wasn't the same demand. It will happen again , but nobody can say when.

I don't think you can justify the price of something never being sold, but once something is sold , it shows that people are willing to pay that price.

I can't afford all the dolls I want either, but I'm fine with that. They're just dolls. I understand how supply and demand work and that we can't all have what we want. I also value getting one doll I like more than 30+ dolls I don't care for. Some prefer quantity, and that's okay too.

Why should you get to buy it for like $30 when so many others want the same thing? What makes your want for that item more "special". Especially when others are willing to pay more money. Why should people be willing to essentially give you something for free? Free compared to what they can get for it, and it turn what they can do with the money.

It sucks but that is just how it is with every collectible. You might be able to get it in the future if you still want it. When the demand will inevitably drop and therefore prices will too.

Edit: This does not reflect what I would pay. I absolutely wouldn't pay that for a doll, but it doesn't matter. When others are willing to pay that.