The people were not instrumental in determining the canon; the Church hierarchy was. Anything that was read in a church was considered "inspired." From the oldest Christian Bibles we know that this included books which are not considered canonical (Epistle of Barnabas, etc.).
The concordance as to which books were inspired and which were not had to be reached among the very people your Church denies, the hierarchs.
My point was that if they collectively did not know the fullness of revealed God's truth, it would have been impossible for them to know which books were inspired and which were not, and therefore the Bible would be a guesswork.
On the other hand, if they were led by the Holy Spirit in their discernment, then you have no authority to dismiss them or their authority as successors of the Apostles.
OK, so to put you and Kolo together, after the Council was done, the laity accepted their discernment. I would say the same laity had accepted the vast majority of it already, before the Council met. Sure, the Spirit led the hierarchs to get all the exact books right, but what does this have to do with accepting their authority as successors of the Apostles? The Spirit leads ALL BELIEVERS, including those of the Council. While this was certainly an important event, it was by no means unique as to whom the Spirit leads.
I'm not sure I would buy into that. The Church made a clear point of separating what was inspired from what was not. When putting together the scripture the Church had a set criteria. They did not consider everything inspired; certainly the Orthodox even in those days wouldn't have considered Augustine's writings to be inspired.