I don't know. I live in Chicago, and while I do get recruiters representing Chicago firms pinging me on LinkedIn from time to time, the majority still seem to come from elsewhere. I also had a tough time finding my next job after I was laid off here, twice in the past three years.
I still love the area so I'm still sticking around for a bit longer, but I don't really see what this guy's seeing.
My impression is that Chicago has a lot of catching up to do in terms of recruitment. The jobs are there, but a lot of places are clueless about advertising them and courting talent. Housing prices are more affordable than the valley, but still high for the median salary here. Really the biggest problem with Chicago IMHO is the aging demographic of the highly skilled sought after developer means they want things like good schools and safe neighborhoods IN their city not an hour outside of it.
I still love the area so I'm still sticking around for a bit longer, but I don't really see what this guy's seeing.