You're way off on this.
Those hourly prices that you linked to only cover the "Electricity Supply Charge" on your bill. Not included are transmission charges, procurement, distribution facilities, taxes, etc., etc., etc. And in order to be on the Hourly Plan you also pay a monthly Capacity Charge that can really add up if you use a lot of power during the highest-demand hours of the year (although if you have solar, it's possible that the Capacity Charge is close to zero, like it is in my case, but most people don't have that luxury).
I'm also on the ComEd Hourly Pricing plan and my actual marginal per kWh cost is closer to $0.08, which is still a very low price and includes lots of off-peak consumption.