In a nutshell: Rahm Emanuel relied overwhelming on large donations from a very nearly exclusively white pool of donors — who also, as further analysis shows, largely live in the same few rich wards of the city (save for non-Chicagoans, as Emanuel also did a lot of fundraising outside the city). Even Garcia's donors were disproportionately white, though to a much lesser extent. "We expected going in there would be some demographic disparities," McElwee told The Week. "But Chicago might be unique in how bad it is."
Now, it's important not to exaggerate the power of money in politics, since much of its power comes from people assuming it's the beginning and end of political power. In the 2015 election, Emanuel had the good fortune of an inexperienced opponent. And the discovery that he had suppressed the horrifying dashcam video of Laquan McDonald being brutally shot to death by police would have certainly destroyed Emanuel's campaign, had it happened before the election. One cannot simply purchase an election outright.