The idea is selling units and making a profit. Residential projects generally aren't ambitious in the U.S.. What's going up in China is ballsy, and you have to give them credit, they pump out 1550+ foot towers like its the ice capades. The U.S. in general is not ambitious compared to our competition which at this point, is China, and they are fast on the road to passing us.
Now, if this was office, and let's say it was 1600' and had a square footage of 4 million sq ft, now... that's ambitious because of the tenants required for it to be profitable and the cost along with a competitive office market. Competitive in the sense that there is a lot of competition for tenants.
But a building geared towards .0001% is not as risky here. At least given the current market. Anything 700,000 - 4 million is a gold mine. It's all relative and depends on the market and location. Timing is everything.