Modern Biblical Criticism has long noted literary and theological patterns in all four cannonical Gospels. In fact, there's no question about it. These patterns DO seem to account for some part of the rationale for how content was arranged in each Gospel narrative. Some, that is, but certainly not all.
If it can be shown (and it can) that each Gospel writer blended together a mixture of directives - BOTH historical/chronological AND literary/theological - in deciding how to arrange narrative content... then the next questions are whether we can identify very much historical sequence of events in Gospel narrative and is there enough to proceed towards reconstructing those event chains from each narrative(?).
If the Gospels were merely stories with theological impetus, they would not have cared so much about facts (people, places) and hinging their narratives on dynamic, game-changing moments. However, since the Gospel writers seem to have brought a mixture of aims to their task, then we should be at least as justified in reconstructing a historical account of Jesus' life as we are in constructing theologies from Jesus' words.