One big change is that most people now had a TV and most of those TVs were in color. The first coast-to-coast TV broadcast in the United States was in 1954 and color was used more and more through the 1960s until it became more used than black and white TV. So by 1975 color TV had been used in the United States for over 20 years already.
From what I could find, the following video from 1958 is the oldest color TV broadcast that was recorded. (Sorry it's not a Super Bowl or baseball game or SpongeBob or something more exciting.) You may want to jump ahead to 1:10. Then when it switches to color, imagine people seeing it for the first time being completely amazed.