The question deals specifically with American life so my response is limited.
America is rapidly becoming a relativistic secular culture accompanied by an indifference to religion and hostility to objective truth. This change is so dramatic that it has prompted Pope Francis to observe, “We are not living in an era of change but a change of era.”
The influence of religion on general American life may realistically diminish in such an environment. The troubling part is not so much the possible decrease of religion’s influence on society but rather the increasing efforts of society to influence the exercise of religion. This should be alarming to all Americans who value our constitutional rights for freedom of religious expression.
In this new environment, the real concern we face is from coercive efforts of society to force people to act contrary to their religious beliefs or reshape beliefs according to secular influences.