Following suit with some of the other answers: economics.
Regardless of how you feel about the local land costs, it hasn’t gotten high enough to support the cost of such structures. Skyscrapers tend to cost 3–5 times the cost of low and mid rises per sqft. Super-tall buildings tend towards 5–10 times that of skyscrapers.
If it costs a fraction of that to build nearby it becomes hard to justify that cost.
Plus, once built you need tenants willing to pay that kind of rates.
MKDesign 