Yeah, but the question is whether a DAG is a good mental model for a VCS. Just because that's the underlying data structure doesn't mean it has to be the user interface too.
So the next major step in VCS technology will most likely do something to help linearize our views and reduce the tangling that comes into play with any tree or graph structure.
a) Most people’s git workflow might as well be linear.
b) rebasing a development branch onto master literally linearizes it
Where git shines though of course is where you can’t get away witha linear model