I half agree with your point.
It is, I would say, impossible to know drive reliability in advance so I understand where you are coming from. On the other hand there are differences which show through when there is a big failure like a lot of the seagate 7200.11 but is far less obvious in the face of a large field of similar numbers.
Genetically we are 99% the same as everything else, that doesn't mean that the 1% isn't important or doesn't make a difference. (I don't know enough about genetics to support those numbers but it is like that and I'm sure you get my point).