No matter what the professor says about his motivations, it's hard to see Saruman's treatment of the Shire as not containing his feelings about modernity impacting an idealized English landscape.  The replacement of Sandyman's old-fashioned mill with an ugly thing intended to grind 'more and faster' can hardly be seen otherwise (by the way, can you concieve of ANY reason why a water mill, however complex, should emit smoke and filth?). 
     So this has to be one of the very few cases where I must say that if the author did not intend a critique, then his subconcious supplied it for him.  Please understand that I LOATHE 'subconcious' explanations for literary phenomenon, and am driven to accept it here only because the alternative, that the shire is not an idealized rural England, and that it's spoilation bears no relation to what was going on in rural England in Tolkien's lifetime, strikes me as nonsense.
     Besides, as we have elsewhere noted, however much he disliked allegory he occasionally used it anyway.  This might be a related phenomenon.