No. The OP is about whether a believer, after he/she is saved, can be "unsaved": It's the same thing. Falling away is to lose your salvation. Its a rejection of Christ.
I believe that when I was saved, I was born again of incorruptible seed (1 Peter 1:23). That's the new birth where the Spirit within you comes alive. This is incorruptible. The person is made up of Body, Soul, Spirit. The Spirit is incorruptible. The Body is total corruption. The Soul is left with a CHOICE. To serve the Spirit, or to serve the Flesh. See Romans 8. The SOUL that sins shall die. Its for our Souls that Jesus died on the cross. The SOUL (inner man) has to decide whom it will serve.
The incorruptible seed is incorruptible. But you are not understanding that scripture.
Incorruptible = aphthartou which means uncorrupted, not liable to corruption or decay, imperishable.
I do not believe a born again believer can fall away to the point you describe in the pages of this thread.
As above....