We all speak English and John 15:1-6 does not speak about losing salvation, although "on the surface" it may appear to.
It amazes how when you quote an interesting statement from a commentary, others will accuse you of not being able to think for yourself, yet iron sharpens iron. So what is the heart of the reason why people (like Judas Iscariot) did not abide in Jesus? Judas was an unbelieving, unclean devil who betrayed Jesus (John 6:64-71; 13:10-11). BTW the word "abide" is from the Greek word "meno" which means to remain, tarry, not to depart, continue to be present. This is not something that only super saints do. 1 John 4:13 - By this we know that we abide in Him, and He in us, because He has given us of His Spirit... 15 Whoever confesses that Jesus is the Son of God, God abides in him, and he in God.
Now in regards to your question, I will share with you what those words in John 15:2-6 mean to me. The
branches that bear fruit and remain are believers (like the remaining 11 disciples). The self-attached branches (cosmic connection) that
bear no fruit and do not remain are not believers (like Judas Iscariot) and those who were offended by the words of Jesus and walked with Him no more - John 6:60-64. In John 15, Jesus mentions
branches that bear no fruit and
branches that bear fruit (vs. 2) but Jesus says
nothing about branches that bear fruit but then later stop bearing fruit.
When Jesus spoke these words in John 15, how many people at that time,
prior to Him being glorified, had received the Holy Spirit and were baptized by one Spirit into one body? - "the body of Christ?" (1 Corinthians 12:13) -- NONE.
John 7:38 - He who believes in Me, as the Scripture has said, out of his heart will flow rivers of living water. 39
But this He spoke concerning the Spirit, whom those believing in Him would receive; for the Holy Spirit was not yet given, because Jesus was not yet glorified. So "in me" is part of the metaphor of the vine, (in the vine) and not in the body of Christ under the New Covenant which was not yet fully established. Without that vital union with Christ, there can be no spiritual life and no productivity. Those who profess to know Christ but whose relationship to Him is self-attached, Christ neither saved them, nor sustains them. Eventually, the dead self-attached fruitless branches are cut off.
And that doesn't describe you? You have Jesus teaching salvation by works in the parable of the sheep and goats, yet you either ignore what Jesus said in John 3:15,16,18; 5:24; 6:29,40,47; 11:25,26 or else try to "shoe horn" works into the definition of "believe" in order to accommodate your biased doctrine. You also have Jesus teaching a loss of salvation in John 15:2-6, in contradiction to what Jesus said in John 6:37 and John 10:27-29. *Hermeneutics.