Even if MOST of the New Testament was COULD HAVE written in Paul's lifetime, it wasn't ALL OF IT. Your premise has been about Paul writing in the past tense and then this is used to try to say that nothing valid can be written afterwards. This is simply not true. NOBODY has ever suggested that John's gospel, epistles or Revelation were written before the end of the first century, are you suggesting that these are invalid?
That has not been my premise.
My premise has been to get you to tell me what those traditions are that are already in place.
So far as scripture is concerned, Jesus established the bounds of scripture.
"All those who believe THROUGH THEIR (the Apostles') WORD."