The Gospel of Jesus Christ has not evolved. American Society and culture is changing and there are churches, pastors and teachers within America that have embraced the culture and have moved away from the Gospel but Jesus has not changed.
The deception within many churches is that the focus is on God coming to fulfill our own desires and wishes instead of us aligning to His will and desires for our lives.
Paul, understood the Gospel of Jesus Christ, when he declared, "I have been crucified with Christ and it is no longer I who live but Christ who lives in me. And the life I now live in the flesh I live by faith in the Son of God, who loved me and gave himself for me.(Galatians 2:20)
The Gospel is Good News for those who were once far from God but have been brought back into the fold through Jesus' blood and His glorious resurrection. It is not good news for our self-centered lives, for the self-centered one must die so that a new creation comes forth in Christ Jesus, where He is Lord over us.
The American form of Christianity is trying to tell us that the way we were born with a particular bent to sin isn't actually sin but should be embraced as coming from God. This is deception in the highest form, leading many away from the cross of Jesus and away from the Good News.