What Dan said! Let me add the programmatic element. When SketchUp became a commercial tool, funding the OpenStudio plug-in became problematic for DOE. Although we want to develop software that is used by commercial products, we cannot develop software that is targeted towards specific commercial products in a given category, while not doing so for others. Why should we fund the development of a plug-in for SketchUp and not for Rhino? Or why for SketchUp and Rhino and not for Revit? Or why ...
Given that the basic workflow needs a geometry editor and viewer, we are exploring a number of free and preferably open-source options as described in the linked post. These will not be "full-featured" options and probably not even as "feature-rich" as the current SketchUp plug-in. But they will hopefully serve our purposes.
At the same time, we would be very happy if others assume the mantle/burden/opportunity of developing plug-ins for commercial products, either free or themselves commercial. If you want to develop a killer OpenStudio plug-in for SketchUp/Rhino/MSPaint and either sell it for coin or give it away for quan (karma), that would be fantastic. That is what the OpenStudio SDK is designed to enable.