This is interesting coverage, but as someone who knows some of the dynamics but doesn't pay extremely close attention to the downtown market, I can't help but notice this article lacks examples from the Loop proper. I suspect things are slower there - "downtown" is several distinct neighborhoods.
chicagotribune.com
As downtown Chicago reinvents itself, demand is high for luxury apartment complexes as building costs rise
As downtown Chicago continues its transformation from a business-focused district into a mixed-use neighborhood with grocery stores, parks and coffee shops, there is huge demand for luxury rentals.