There are many churches devoted to the Lord. If the Catholic church were to fold, the many other churches would cover he fort. I don't see those who seek the Lord suffering that much. Not all Americans are of the Catholic faith. Many are not. There are missionaries of other faiths helping those in spiritual and physical need. The Salvation Army is also where they're needed.
Not to sound crewel, but the world would go on anyway. The Lord would see to that.