Wow, that goes way back! And people here consider themselves practically a native if they've been here 20 years.
Missing California is puzzling. If you look at the growth of cities around the world it's generally the coastal regions and port cities that have more population than interior regions. The predictions about Salt Lake and Denver are also strange. There just isn't enough agriculture and water around here to support a metropolis the size of New York. The prediction about Chicago is more understandable as in 1893 it has seen incredible growth in a short time.
They missed California because they didn't know about the oil and the agricultural possibilities (the San Joaquin Valley had to be drained). But they were right about Chicago, which has become a megalopolis in its own right, stretching from suburban Milwaukee down to Hammond and Gary.