"Germany and Geneva began with persecution, and have ended in scepticism. The doctrine of infallibility is a less violent hypothesis than this sacrifice either of faith or of charity. It secures the object, while it gives definiteness and force to the matter, of the Revelation." (Newman, Essay on the Development of Christian Doctrine, 91)
Of course Newman is speaking from the European perspective on this matter (Germany and Geneva have resulted in something relatively different here in the States), but his point remains cogent. It would seem that the doctrine of infallibility, pronounced ex cathedra by the pope in the 19th century, was likely a response to issues around revelation and Christendom of that time. The doctrine was not espoused until that point because it did not need to be articulated in that way in the preceding centuries.
He thus is making two points. 1) Doctrines develop for the sake of necessity, they respond to needs. 2) Doctrines that come about through this process of development are not necessarily wrong simply for being new. They are rather that which comes from that which came before, but responding to a new historical situation.
The Lutheran church, at least in its ELCA manifestation, lacks the appropriate resources for the proclamation of doctrine in new situations. We write social statements, but seldom if ever make new confessions. The reason for this lack is manifest- what magisterium is in a place to declare it? The bishops tend to concern themselves with "practices", ELCA churchwide concerns itself with liberal social issues (I may be stereotyping here for the sake of brevity), and our ecumenical theologians make ecumenical statements, but who can really speak in our church ex cathedra for the sake of renewed proclamation of the gospel. What is our magisterium? What parallel do we have for infallibility?