I don’t know about the US but Point 1 definitely resonates with me.
I grew up in the Republic of Ireland during the 1980s when the vast majority (more than 90%) of people identified as Roman Catholics. I took it all very seriously (prayed multiple times each day, read the bible, a little theology, lives of saints, etc.) but my fellow Christians didn’t take anywhere near seriously: attending Mass on a Sunday, first communions, confirmations, weddings and funerals. While they might vote against abortion and divorce and send their children to Catholic schools, their beliefs didn’t really impact their daily lives.
Some of my parents’ generation believed in the efficacy of prayer:I always had my other and other relations praying for me during exams and if anyone was ever sick or having medical treatment, they would be prayed for. But most of my own generation didn’t share this belief in the efficacy of prayer. They certainly didn’t buy into the concept of Jesus/God being an integral part of their lives.
The Catholic church had the dominant position, so other than controlling educational, medical and other institutes, it provide its members with the same sense of community as that of Church of Ireland and other minority religions.
On the other hand, with its diversity of Christian churches, north of the border was much more like how you describe the US. The identity with religion was (is) much stronger as it usually corresponds with the individual’s national identity (Irish or British).
Note: Support for the Catholic Church in the Republic declined drastically in the nineties when the church lost its moral authority as news came out about how the hierarchy had facilitated child abuse and various other scandals.