Robert's right. The two cities can't be compared.
Dubai's growth is very impressive but it is state mandated growth meant to attract tourists. Many of they're skyscrapers are built on spec while NYC tends to wait for the free market conditions to necessitate building something.
Take 2wtc for example. While we'd all love to see it built and we have opinions on what silverstein should do, he's not constructing that thing without an anchor tenant.
While I really love some of the buildings over in Dubai and wish NYC would make some megatalls of their own, I think it's better to build something that you actually have the money/need for instead of bankrupting yourself on unnecessary bombastic projects.
This short article from natgeo is kinda neat if you wanna read more about it: http://onward.nationalgeographic.com/2014/09/10/why-dubai-is-growing-so-fast-and-may-eventually-slow-down/