With every passing day I apply scientific signals analysis triangulation techniques to study the Gospel parallels, the more patently obvious it becomes that Gospel of Marcion was a much earlier text that Late Luke (or what some scholars anachronistically call “canonical Luke”). Sure, there are lots of parallels between Gospel of Marcion and Late Luke. But why is it that Gospel of Marcion is usually missing distinctive Markan traditions and is almost always missing distinctive Matthean traditions that Late Luke incorporated?
Matthew interpreted Mark and added distinctive traditions. Those distinctive Matthean traditions are all over Late Luke, and yet almost entirely missing from Gospel of Marcion. That is game, set and match.
There is no way that scholars any longer can maintain that Gospel of Marcion was an abridgement of Late Luke. It was clearly an early version of Luke, one with a significant amount of materials that predated Mark, and some segments that postdated Mark, but all of which predated Matthew. Matthew frequently borrowed from Early Luke (Gospel of Marcion), not the other way around.
Late Luke (117-138 CE) was a later massive synthetic project, one that drew not only upon Qn, Mark, Early Luke, and Matthew, but also upon the Gospel of John.
The direction of early Gospel texts is overwhelmingly toward synthetic expansion, not piecemeal abridgement. The early orthodox heresiologists wanted us to think Marcion represented a later vivisection of canonical Luke, when the whole time Marcion was actually a faithful representative of the Third Gospel ever composed, a Gospel which early orthodox compilers could not destroy even as they attempted to replace it with Late Luke.