Prices aren't tanking, they simply are stabilizing if anything.
Pinside statistics are all kinds of wrong cause it only represents a tiny percentage of machine sales, majority of sales on pinside are not concluded through the pinside system so even if you contact someone to buy, it's usually done off site and no info is updated such as final prices, what was offered, and so on. Items with high prices that don't sell and sit there also skew info. Price data also doesn't consider condition of the pin, reasons, and stuff like routing. Yea I've seen some crazy prices on routed Aliens for example, that info is going to skew the data, but it's also a worn and routed machine so it's typically sold for less and priced to move. Batman 66 sells for a high asking still, but have seen "need to move it fast" sales for thousands less than normal asking. Again, such info skews overall statistics.
Well I saw this pin for sale for 3k less than retail original price! Ok... well that's just one case, ignores all the games sold elsewhere for a higher price that aren't recorded on pinside.
I think folks are seeing the prices cooling in general, having to reduce some prices to be competitive if anything, but tanking, nah if prices were tanking I would be buying a lot more pins. We got more pins than ever coming out, lot of folks buy new play for a bit and quickly flip for what new hotness is coming in. The manufacturers are back on the ball and producing more than ever, more companies making pins, more inventory, this is just price corrections after the couple years of pinflation.