Yep, it white-flighted out to the suburbs. My dad's two siblings kept their accent but my dad suppressed his, either when he was at Loyola or at U of C, because he didn't want to sound like a low-class south sider.
You'll still find it in certain neighborhoods, Beverly comes to mind.
agreed, probably due to amount of youth in the city. growing up in the burbs of chicago i heard my family talk like this, mainly the men. Dad, uncles, you would hear a lot of 'trow some sausage on der' type phrases. Also instead of Jewel (grocery store) you hear "the Jewels".
You'll still find it in certain neighborhoods, Beverly comes to mind.