They still have time since this will go up in phases. So phase one will include the bottom portion, station, and retail with the larger towers coming later on. With sometime like this, they will have to get approval before it rises. Certain projects have gotten away with it receives FAA approval when they are half way up), but being over a 1000 feet, the FAA will have a tantrum.
But hopefully everything goes as planned. There are also the other supertalls that will go up in the future (lets hope).