Bob Dylan has always sealed his decisions with the unexplainable. His motives for withholding the release of the magnificent 'Basement Tapes' will be as forever obscure as Brian Wilson's reasons for the destruction of the tapes for 'Smile.'
After all sustainability means running the global environment - Earth Inc. - like a corporation: with depreciation amortization and maintenance accounts. In other words keeping the asset whole rather than undermining your natural capital.