This is an unsubstantiated claim. Certainly, there have been a fair amount, but not for lack of effort on the OS developers' parts. It can always be better, a

This is an unsubstantiated claim. Certainly, there have been a fair amount, but not for lack of effort on the OS developers' parts. It can always be better, and cutting edge, modern OS designs are superior, but it's not like the foundations of NT/Darwin are completely rotten.