America is a product of Protestantism. As Protestantism has been undermined and supplanted so has America and the entire West.
I grew up in what was in essence a Dutch Reformed church which later joined the farcical "United Church of Christ"
I don't think protestantism has been undermined - I think it's a failure, and that its fate (in retrospect) was perfectly predictable from the days of Luther and Zwingli.
If the only structure of the Christian Church from the beginning was house churches and evangelical local churches, the whole thing would have been over in 200 years and no one living today would have ever heard of Jesus Christ.
Whether the Western Church, or what's left of it, can survive Francis remains to be seen.