yah, actually, you're wrong, mr nice isn't a breeder, but shanti is, and he's the breeder who used to be half of greenhouse seeds back in the 90's when ghsc made all of the cup winning strains.. it was all of shanti's hard work and genius that made greenhouse who they were back then, but in the mid 90's he left arjan and greenhouse seeds and went on with howard marks, who is actually mr nice, the famed smuggler, to form mr nice, also with neville shoenmaker, another infamous breeder..
but anyhoo''s, on to the op's question.. like someone else already said, one company or person will create a killer strain, like your sample of ww.. it sells well all over the world, but sense the cannabis world is generally unregulated per se, many other companies and breeders will come along and try to use the name ww to sell what ever genetics that they maybe using under the same name..
of course it's impossible for every breeder to have the same exact parents so i don't see how they could possibly have the same strains.. it's all bs, and it really does pay to do your homework when looking to buy certain strains..
it's not to say that sometimes a knock off strain can't be better than the original, but that rarely happens, just make sure to do your work...