I agree with your argument but what I do not accept is that much as it works at your outfit it might not fit into BA's model and that's why recruitment would be keen to identify similar candidates this by say unsettling them with test you described as 'irrelevant tests, interviews which aren't fit for purpose'. BA's secret in recruitment falls between the lines of lateral thinking (thinking from outside the box) to arrive at what you want. Only those who align with BA's point of view get the nod.
It has worked for them over the years; why would you change a working formulae just because they think you should change!?