Catholic opinion does not seem much different that American opinion as a whole. Catholics have regressed to the mean. That is what tends to happen in a culture as open and democratic and seductive as the American culture. That's my take.
You're pretty much right on. People slot religion into a space on Sunday morning (if even then), then absorb the zeitgeist the rest of the week.
Most of the disagreements, you'll note, are in the area of sexual morality. That's been the Achilles heel of the Church from the time of Christ. The thing is, Jesus didn't dwell all that much on sexual morality. He was more concerned with caring for the poor and our attitudes toward each other (basic charity).