The operative word is "we", as in Paul and the other Apostles. It does not follow that "we" includes the self-appointed RCC. It is God's providential goodness that led to God-fearing men to preserve the writings of the New Testament.
If that's the case, it does not follow that the word "you" includes anyone but exactly who Paul was writing to, and not self-appointed Christians of the 21st century.
True. Paul as writing to whomever he was writing to. However, that doesn't mean that (a) those writings are always exclusive to the intended audience; (b) we can't learn from his advice to them. This is why it's so important to read Scripture in full context, and to apply the Word accordingly.