Those who teach salvation by works are not Christians. There are genuine Christians and there are “nominal” Christians. In regards to abiding in the vine, Greek scholar AT Robertson explains that there are - “two kinds of connections with Christ as the vine (the merely cosmic which bears no fruit, the spiritual and vital which bears fruit). The fruitless (not bearing fruit, mh peron karpon) the vine-dresser "takes away" (airei) or prunes away. Probably (Bernard) Jesus here refers to Judas..”
John 15:2 Commentary - Robertson's Word Pictures of the New Testament
One must truly be born again to abide in the Vine, such a one is in the Kingdom of God.
One who is only water baptised does not truly abide in the vine, such is of little faith, nothing wrong with such, we have all been their, but one would hope for greater faith, well I did ! I was always seeking more and one day I had an encounter with God and bingo I knew him 100% total faith in Him, no doubts at all anymore what so ever ! it was much like what happened to Saul when he became Paul. I was blown away. I love that Johnny Cash Song, 'I saw the Light', it's totally true. my brother in law said that song is not true, he claims their still is sadness, well no there is not any sadness in my heart and Soul in fact, as I have the Lord Jesus abiding in me and me in him. Praise the Lord ! I am not Sad in myself ? my Soul is lifted on High, but I maybe sad for others.
I was sceptical of everything but that's just how I am from 6yo I suppose, I never did not believe my school teachers 100% I would even question them at times, I did not just let things go, thinking oh well who cares about anything or just believe in something that you do not understand I can not do that.
I do not believe in blind faith. I had faith in Christianity at that age and it always grew and devout even willing to die for such faith but maybe I could of came to a point like many at bible study did, as the years when by and they fell off the tree, there faith was dashed, that was the majority of all who I knew from them days. I am so glad that I have total Faith in Jesus Christ, now the Church denominations are not my bag, but Jesus Christ sure is.
Look at the Churches nowadays, they are like you say, the people are dropping off, because they are loosing the faith and why is that ? it's because they are not drinking from the spiritual Well, for if the Church did preach Jesus Christ first and foremost in peoples lives, they would not loose them at all. If one of faith sees such as that in the Priest and the faithful such will give them strength to keep enduring in the word of the Bible and Christians all around them. asking questions getting little by little food for thought, I believe one has to strive and give it your all. with your whole heart, Soul, Strength, Mind and strive to enter at the narrow gate.
If I started preaching Jesus Christ in the churches of today the people in them would not like such because they would be offended ! Remember Jesus offended some people and they came in want to kill him, because Jesus offended the poor miserable bastards, they would be better off to put a millstone around their neck and toss it into the sea.