IMO, what's happening in Vegas is that a lot of people who swooped in and bought houses when the bubble burst and trying to become mini-millionaires off of their investments.
Houses that went for $120,000 four years ago are listed for $400,000+ for no other reason than people think they can cash in, and see all the other listings for the same unrealistic prices, and they're trying to "get theirs while the getting is good."
The problem is that they've priced themselves out of the market, since very few people who move to Vegas are tied to the city. They just move elsewhere. So there's lots of houses sitting around with $500,000 price tags on them that aren't being bought because they're simply not worth that much.
I base this largely on three people I know who are currently trying to sell their homes. The person who best exemplifies this is a guy who bought his house for $200,000 in 2014. He's trying to sell it for $459,000 now. Why? No reason. He just thinks that he can get that much for it.
People have to stop using houses as piggy banks.