Saying "why can't our waterfront be more like Chicago's?" is like saying "why can't the AGO and ROM be more like the Louvre and the British Museum?" You're comparing Toronto to quite literally the best in the world at that one thing. No one has a waterfront like Chicago's except for Chicago, and the only reason it's like that is because of the culmination of 200 years worth of planning and circumstance: Plans for the city 200 years ago called for Grant Park. Throw in the fact that the Adler Planetarium and the Shedd Aquarium were only built because two wealthy men donated a lot of money to have them built and the Field Museum and Art Institute only exist because they held the 1893 World's Columbian Expo. Finally, and perhaps unparalleled anywhere, the private sector paid for half of the nearly $500million cost to build Millennium Park. Also keep in mind, we're talking about a period (city beautiful movement) when grandiose and ambitious structures and plans were the norm around the world. Toronto has a few remnants of this era, but we're talking about comparing us to a city that was one of the wealthiest in the world during that specific period and perhaps at the forefront of the entire movement.
However, the other thing is, Chicago's waterfront isn't a welcoming place for locals. It's primarily a tourist destination. Toronto's waterfront is filling up with condos (for better or for worse) and it means that the area is far friendlier to locals. It's another neighbourhood, not an attraction. Essentially, if something like Chicago's waterfront is what we want (for some reason), then we should start looking at the Exhibition grounds as our own Museum campus/designer park. We already have the buildings and the Princes' Gate. You just need to tear up the parking lots, replace it with parks and fountains, kick the CNE out, find uses for each building and you're good to go. But there's no point wishing we had a Chicago waterfront between Spadina and Parliament. That ball had to start rolling before any of our grandparents were born.