It's obvious to anyone outside the aviation bubble - that if the unions create this enormous inverted pyramid, with massive seniority determined T&C benefits for those at the top, for doing essentially the same job as those at the bottom .... then it is just an "accident" waiting to happen for the whole lot to be pushed over, with all the scales crashing down to the ground level.
Unfortunately (and probably as a result of the above) at BA, the ground level is very very low.