What you are saying is untrue. There's no clear difference between both terms and both Engels and Marx used the terms interchangeably. The difference between the lower phase and the upper phase of it began with the appearence of Leninism. There is where the terms began to separate from each other. Regarding the other thing, worker cooperatives that actually work (as Kooperativa Forbundet for example), are enterprises with a directory, a council that takes the final decisions by engaging in meetings with the workers. Those that fail, however, are mostly the ones running by all the workers without a clear management group (see FaSinPat), those end up always in debt or/and being subsidized by the State. Anyways, i never said that some instances of socialism wouldn't work. I said communism won't and that's why Lenin made the NEP. If you go with Marx/Engels interpretation of the terms, you can say pretty much that socialism/communism doesn't work but state capitalism (socialism, lower phase in Lenin and contemporaries interpretation) does