Boeing refuses to change it, relying on "grandfather" clauses to persist with a warning system that would be permitted on no new aircraft design. It is not a question of endlessly adding new warnings, but of getting rid of bad ones and conforming to modern manufacturing and design standards. And as for the human factors issues, competence etc,. it is a truism that, as remarked above, the best pilots can have the worst accidents. The critical path here is about accurate and unambiguous warning devices, not training or airmanship deficiencies
And that is the correct answer.
The fact the two pilots were too stupid to see the error is the not the case.
Why make such a ridiculous "fail non-safe" system" ?