I am not sure how to put into words what I am thinking.....
I think I understand your point, maybe we should examine 'dead faith' as being 'false faith'? Now I am not one to be judging a person's salvation-that is betwixt you and the Lord. So please don't anyone take it that way.
Much of Christ's rebuttal against the Jews was about their false faith-I mean Jesus called them children of the "devil" while in the temple! Pretty strong stuff against the religious authority and the 'faithful followers'. John 8
Faith in Christ (which includes following His commandments John 14:15, Matthew 22:36-40, John 13:34-35) is all you need-His Grace-His Works give us salvation. Not anything that we can do. 1 John 2:2, 1 Peter 2:24
1 Timothy 2:1-6
2 Peter 3:9
Acts 10:34-35
John 3:16
Matthew 28:18-20
Mark 16:15-16
Revelation 22:17
Think about the key figures in the Bible like David, Solomon, King Saul, Adam & Eve, Moses, etc.....They ALL fell. That doesn't mean they lost their salvation.....
I think you put it into words just fine you old DRS!