Again and again I've gone into the details of people's criticisms of scrum, and again and again it's turned out that they were just not actually doing it. Actually doing scrum does work 100% of the time as far as I can tell.
It can't be both things at the same time. (out of curiosity, you say 100% of the time, how many companies you worked for that did scrum perfectly and had 100% good results?)