the whole selection process is SOOOOO political - and I think 1/2 of the decisions are made to "stick it" to the USA. I'm not surprised that Chicago was not chosen.
As for eliminating Chicago first - that's the "stick it" factor.
I figured it would be Rio - whatever objections are floating around out there will be ignored in the interest of geographical equality and giving the "new guy" a chance.
Look for Chicago or another North AMerican city to get the nomination for 2020 - and then back to Asia or Australia in 2024. Europe again in 2028.