2008 SUBARU FORESTER Visibilitywiper Problems

WE PURCHASED A SUBARU FORESTER 2008 IN THE FALL OF 2007. AT ABOUT 4 YEARS, OR 40,000 MILES THE PLASTIC HEADLIGHT LENSES FOGGED OVER, REDUCING LIGHT OUTPUT AND DISPERSING, NOT FOCUSING THE HEADLIGHT BEAM MAKING IT DIFFICULT TO SEE THE ROAD AT NIGHT. MY HUSBAND SPENT TIME USING PLASTIC POLISH TO REMOVE THE APPARENT FOG ON THE PLASTIC-HEADLIGHT COVER. AT THIS POINT THE LENSES WERE CLEAR AND UN-FOGGED. AFTER LESS THAN TWO MONTHS THE FOG ON THE PLASTIC-HEADLIGHT LENS REAPPEARED. I BELIEVE THIS TO BE A MANUFACTURER'S DEFECT. SUBARU USES SOME SORT OF PLASTIC THAT IS EXTREMELY SENSITIVE TO ROAD-DUST ABRASION. THIS CREATES AN UNSAFE DRIVING CONDITION WHEN THE HEAD-LIGHT BEAM IS DISPERSED RATHER THAN FOCUSED ON THE ROAD-NECESSARY FOR NIGHT TIME VISIBILITY. SUBARU HAS DENIED THIS IS A MANUFACTURER'S DEFECT. THEY WOULD BE THE LAST TO ADMIT THIS. THEY HAVE SAID I COULD REPLACE THE HEADLIGHT LENSES AT A...