I wonder how much of this will go unused. The "largest mall in the world" was build in China in 2005 and has remained 99% vacant. Having the "tallest building in the world" is an even bigger feather in their cap, but it won't be very impressive if no one actually uses it.
The Empire State Building didn't reach profitability until about two decades after its completion. Nevertheless, it has remained impressive from the time of its completion through today.
Centre Point in London ("just" 34 floors) was left totally empty for the better part of a decade after construction because rising property prices combined with the owners desire to let the whole building to a single tenant made them consider it beneficial to just wait it out until they could find a suitable tenant... Commercial property development can be pretty weird.
The Empire State Building completed construction right before the Great Depression. The Great Depression was followed by WWII. The ESB became profitable as soon as the US economy picked up.
In contrast, the Chinese Great Mall has been essentially vacant despite China's decade-long boom cycle. If they can't fill up the mall during a period of double-digit economic expansion, they never will.
