They didn't fail after a year or so, they failed when dust particles got in there because it was physically impossible to make that design not do that. They reworked it and reworked it but it just couldn't be done. Finally they admitted it was a mistake to require that level of thinness from a design standpoint.
But putting that aside, I still see that as an execution flaw, or at least, it's a way in which design and execution are so intertwined that the distinction no longer makes sense. A computer with a non-replacable keyboard that breaks after a year is a badly-executed product. The way to execute it better would be a keyboard that doesn't break, whatever design decisions that entails.
The way I see it is those doing the executing were handed an impossible constraint. Immediately upon having that constraint loosened, the keyboards became pretty much perfect.
