No... for one, NURBs geometry is pretty particular (e.g. each patch must have exactly four sides), and in this case, the flow of information is from the NURBS to the poly. That's why there is history attached to the poly object. Its shape is dependent on the NURBS shape. If you want to disconnect that flow of information, you must delete the history on the poly object. This is a pretty fundamental part of how Maya functions at a base level.