Ironically ,modern enemies make us aware how important tradition was to the forming of the canon. Especially those who love the ancient gnostics and tout the Gospel of Thomas denounce the Church for suppressing this and many other heretical books, which for them the “real” truth.
That’s an excellent point. If they didn’t have these Church Councils guided by the Holy Spirit, they probably would have just shoved all those other extra-Biblical documents that were floating around back then into the New Testament too. (Like you are saying, the “New Agers” of today are inadvertently highlighting the importance and necessity of those early Church Councils.)