Phones on bones fall mainly on the stones, or maybe on a strip of sidewalk that isn't being used for anything better. Who can say what logic may have influenced the decision. It probably cost someone a fair chunk of money. Then again, if someone paid, someone else was paid.
Checks and balances. Credits and debits. Everything evens out in the end, they say, and though that may not always be true on an individual level, the universe knows. It holds true. Conservation of mass and energy, or some such.
That's one way to look at Chicago. It's a limiting worldview, to be sure. Very reductionist, a thing that suggests no other possibilities. The best way to think about it is that the sidewalk had potential to be the base of something else. Still does, really.
What might that something else be? This is where imagination comes in handy. If we knew a clever person or three, we could get a few informed opinions on the matter. Serendipitously, we might find such people walking on the very sidewalk we are trying to improve. Walking, talking problem solvers.
Actually, that's not a bad description of humans. Alternatively, you could call them walking, talking problem makers. We make problems, we solve them. Credits and debits, right to the end.
The thing about art is that it forces us to think. Often those thoughts are along the lines of, “I could have done that” or “I can't believe someone got paid to make that.”
Sure, but it's like how the sidewalk has potential until someone does something with it. Of course you could have done that, but you didn't, and that's the difference. Maybe you had a crazy idea in your head. If you'd acted on it, you might have gotten paid.