[aaron38]

There was a tremendous boom in the Metra burbs from 1998 to 2007. All the low hanging fruit, all the big parking lots, burned out strip malls, crumbling buildings, all of that went. Those towns experienced a tremendous growth of condos, townhomes and apartments. For the most part the big empty blocks are gone and what's left is smaller scale infill. As ardecila said above, that infill is happening. But it's not going to be the percentage growth it was before. It just can't be.
The burbs are always going to be a sea of single family housing (lots of tear down rebuilds BTW) with a tiny knot of mixed use buildings around the Metra stations. Burbs that don't have Metra won't even get the condos, aside from scattered senior housing or low income apartment blocks along major arterials.