I understand what you are saying, however mere men decided which scripture would be contained in the Bible. Lots and lots of scriptures were circulating at the time (@400 AD) and therefore, men (what the Catholics would call the Church) had to codify, decide what was in and what was out, decide which were inspired and which were not and then choose between scriptures that were supposedly written by say, Paul, but there were several slightly different versions of the same letter around.
I'm hearing that you trusted those men who put together what we call the Bible, I think. Now, if you think that God inspired those men who codified the bible, then you must believe that God can inspire and lead to truth, right? Did He stop with the apostles and start again about 400 years later for a few years while the bible was codified and stop again after that? And then we are left on our own with the Bible (codified by men in the 400s) as our only source of Truth? And if the Bible is our only source of Truth, how did the JWs or the Mormons or the Calvinists or the Pentecostals or the Lutherans or the Anglicans or the Fundamemtalists or the Baptists arrive at sometimes very different understandings of God and his plan of salvation?
And I keep coming back to "I will be with you until the end" when I read your "No human could be expected to perfectly pass on the faith because every human makes mistakes." Was He kidding around?