If Paul died in about 67 or so, then we are saying that the 3 synoptic gospels, all of Paul's letters, James, Hebrews, and Acts could all have already been written.
That would mean that most of the NT was already written before Paul's death.
Did you read the post on qumran's 7Q5 that I sent you?
Revelation certainly wasn't.
Further even if all were written you've done squat to assert St Paul was intimately familiar with each and that the churches he was writing to had a collection of all of them. (History asserts they most likely had one or two at best).
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?