But I still challenge the fact that it can really work well for normal performers and not only top notch developers. Taking care of all the phases of a software

But I still challenge the fact that it can really work well for normal performers and not only top notch developers. Taking care of all the phases of a software lifecycle is not an easy task, it has a big enough cognitive load. I understand that this is supposed to be done in (small) teams, but within those teams you still need some degree of separation of labour, you cannot have everybody having wide and deep knowledge of everything software. Well, you can do it, if you are Google and the like and set the bar for hiring really, really high. But that doesn't apply to most organizations and engineers. Not all of us are wicked smart.