BOSE 301 Series III bookshelf speaker?

Series III are considered the best and the most demanded of all the entire Series? II's are good too. IV's changed everything with Plastic shell?!? V's are lightweight and not in the same hemisphere. Also BOSE 301 Series III are the heaviest at 31lbs and were well-crafted. Why did BOSE stop making these and go to a lighter plastic and ultimately a smaller shell and shoddy craftsmanship?