The original point of the graph (and the sub-article) was that the Packers had, after a long climb, passed the Bears in total margin of victory. It gave the rest of the teams info for historical comparison.
If you want a graph to show you who has been good/better/best in an era, then get your little wet nose over to Pro Football Reference and pull the data.
Here is the link, though PFR only goes back to 1940: http://goo.gl/WIB2Wp