Unfortunately/fortunately, LIFO is a fact of life with many companies. The trouble with any seniority based company is just that.
However, pilots for any big airline (BA sized) are in a seniority based industry. We can't just up-sticks and move to an equivalent position at another company. For example, my next career move would be to become a shorthaul captain. If I left BA to join Air France (for example, assuming I could speak French well enough), I would have to start at the bottom of the pile again, on Pay Point Une and probably as a shorthaul co-pilot. Sure, I could become a Captain in time, but I would put myself seven or eight years behind my current position. If I worked in the City, for example, a sideways/upwards move is the norm between equivalent companies. I think ground engineering works this way too (although not necessarily at BA perhaps?).
The reason we have twenty four pay increments for each rank is recognition of the fact that we can't make sideways/upwards moves with other companies. In a way, it's a loyalty bonus. I'm not saying the system we have is right or wrong. However, it is the system I was recruited with so it will have to do. As things stand, I would be mightily peed off if someone was recruited to BA tomorrow to take a command which I have been waiting for loyally for x years.
Without a seniority system (this is world-wide, not just BA), if I felt I could make a good career move by going to AF, say, I could go there as a shorthaul captain on the best deal for me and perhaps re-join BA in a few years as a longhaul captain if the deal suited me.
The only way to do this is to remove seniority lists from airlines worldwide which will never happen. Just to emphasise that I'm talking about companies of a similar size to BA (AF, LH, AA, etc), not lo-costs or regional operators.
So that is the reason why we keep LIFO and a seniority list at BA.