This is an odd time for Uzi's. I think they're feeling pressure from M11/9's. Between Lage, CFW, and now 5.56 and AM180 uppers the M11/9 is becoming the "poverty sear." I'm going to speculate they won't sell and appreciate as fast as they would with M11/9s out of the equation. The same may be said for FNC and AC556s... we'll see.
Years back many folks I talked to wanted Uzi's because MP5's were too expensive, but it was more enjoyable to shoot than a bullet hose M11. Now, the tables are turned and many guys don't want an Uzi because they don't have the versatility of an M11/9 and cost more. Those folks weren't after an "Uzi" specifically - they were after a 9mm sub gun that they remember from 80s movies.
I would say market price for Uzi's is 12-15. I don't think the fact that ones at 14 aren't selling fast is a reflection of the actual market PRICE, but rather demand is lower, so more 12-13k ones may be found for sale. (Guy's just aren't snatching them up as fast.) Because there's better deals on the market due to a lack of demand doesn't necessarily mean the price went down, just means you can buy at the lower end of that spectrum easier right now.