From an admittedly cursory look at BA's annual reports it would seem that Cabin Crew cost about 5% of BA's total costs. (Total, all employee costs, 29%)
So on a nominal flight, where the fare was say £100 , the cabin crew would cost the passenger £5.
How much would the tip be on a restaurant bill of £100?
So why are they trying to squeeze a few ££s out of 5% of total cost?
I am sure that there are lower hanging fruit elsewhere, and this brouhaha is not really about cost reduction, but power and the perception of power.