The previous owner thought the same thing. He originally bought in in 2010 for $2.8 million. He tried to sell it a couple years later for $22.5 million. A little over a year later he came down to Earth and tried to get $5 million for it. Right before it got foreclosed on, he tried to unload it for $4.4M Bank took it and put it on the market for $4m with no offers. Cut the price 1/4 million, finally got an offer for $400k below asking. It's almost impossible to get a home sold for over $4m in Vegas because there is so much available and so much to choose from.
Water level is getting pretty low in hoover dam though. I know Vegas doesn't get much power from the dam as most of that energy is sold to CA and AZ, but it's still going to be a shit show in a few years when the dam stops generating power. The water level right now is 1088 feet and will probably drop to 1068 by end of summer. The dam has concerns if they can generate below a 1050 foot water line. Water level seems to be dropping about 10-15 feet per year on average.
There is a countdown clock on the website of the las vegas sun of when they will run out of water.
https://lasvegassun.com/news/topics/water/
Some people don't believe it though. It's a little like climate change. Some believe, some don't, both give evidence but nobody will know for sure if its true until it's too late.