The Roman Catholic Church dwarfs any other church on the planet, and it makes the tiny US denominations look miniscule by comparison. They are hardly on life support.
EVERY US denomination, except for the Assemblies of God, is losing members according to the last report that I read.
Catholics, however, seem to maintain their US numbers, if for no other reason than because of their higher birth rate. Meanwhile other US churches are telling their faithful that it’s fine and dandy with them to discontinue raising families.
You need to be more careful what reports you are reading because that just isn't true.
Just as an example:
The Presbyterian Church USA is the largest Presbyterian denomination in the U.S. PCUSA has approximately 10,038 congregations, 1,760,200 members, and 20,562 ministers. The denomination has been steadily losing members and churches since 1983, and has lost 37 percent of its membership since 1992.
On the other hand, an intirely DIFFERENT denomination .... The Presbyterian Church in America is the second largest Presbyterian denomination in the U.S. The PCA has approximately 1,808 congregations, 367,033 members, and 4,416 ministers. The denomination has been one of the faster growing denominations in the United States, growing tenfold since 1983.
Let's not kid ourselves. The ONLY reason the Catholic Church in America are maintaining it's numbers is because of illegal immigration and the fact that the 10's of millions that are here illegally are Catholic.
There are a lot of Catholics in this country...but the number who are cultural Catholics...who never attend mass....who only show up at weddings, funerals, Christmas and Easter...is at an all time high. They identify as Catholic but you would not know it if you checked their schedule.
And THIS is not just a Catholic problem. This is the state of religion in America. ~80% of the country identifies itself as Christian....but they are not. They are cultural Christians...CINOs (Christians in Name Only). They are no more Christian than Obama.
Calling yourself a Christian doesn't make you one...just like calling yourself a woman when your Bruce Jenner doesn't make you a woman. Going to Church or Mass doesn't make you a Christian either, just like going to a doughnut shop doesn't make you a cop (ok...cheap shot).