Umm, is that really that much over a 75 yr contract? $1 invested in the stock market 75 years ago would be worth $172 today and that's adjusted for inflation, which I don't think the 10x figure is. To get to where we end up with 11x after 75 years in nominal dollars we're looking at just north of 3.2% interest.
So basically Chicago got a 75 yr loan at just over 3.2%. Currently 30 yr muni bonds average almost 4%. They'd have been lower back then, and I'm not even aware of 75 yr bonds existing, but what works out to a 3.2% interest rate on a 75 year loan is far from a disaster.
This article was not written by someone who understands finance, so I may be taking too much from that one quote. But if all they're getting over 75 yrs is a 10x return, it's hardly abusive! The investors would have been much better off just buying ETFs.