The problem is you can't just hit a button and combine these apps. Plus, I see Vectorworks very differently than ArchiCAD/AllPlan. I use Vectorworks for concept work (color 2D), 2D drawing, site planning, terrain and massing models, interior design detailing, marketing documents, and even component modeling (like many do with Sketchup). I use an app like ArchiCAD and AllPlan for my building information model. Even though VW can technically do this work, I think we all agree its not the best. Yet, it is the best for the items I use it for.
I know a ton of people that use VW in ways Archicad etc wouldn't be considered - ie sound/trade show booth design/stage design etc etc...