Is Chicago lost on film during Richard J.'s term?

[Slithy Tove]

Reading the wiki article on the Blues Brothers, it mentions "Mayor Richard J. Daley had all but prevented films from being produced there up until his death in 1976"
A cursory look at IMDB of the 2,000+ "filming location: Chicago" does show a large gap in from the mid-1950's through the1970's

Does this mean that in the 1960's Salt Lake City was better-documented, due to "Carnival of Souls," than Chicago, or am I blanking on a bunch of movies?