Discontinued Items

Why do these exist? I can understand that you have items that are cosmetics but there are actually good items (like Santa stuff). Also why did some items have been discontinued?

 

Santa items were all limited-time (though I think Meaningful holiday still gives a piece) to incentivize playing.
From what I understand, Pumpkin heads were (and still are) super-valuable, and there was a dupe. It damaged the economy.

That's all I know of them.

 

I get that they were collectors items but why do they have so good stats? And did they plan to discontinue them?