A truly level playing field would mean internalizing all externalities. If that were possible, yes, that would be ideal, but as he just noted, it's really unlikely, partly because it's enormously complex.
That's actually just your definition of a level playing field, there is no 'true' level playing field. (Well, other than literal playing fields that are level)
It doesn't seem possible for solar to make that much progress in that short a time.
It takes forever to get transmission capacity approved and built to areas where solar is really cost-effective and we still don't have grid-scale energy storage.