Something that strikes me is that Ba pilots have a nice life with many perks when compared to other airlines - some airlines pay more, some (all) give better short to medium term career progression but pretty much none offer the balance and extra perks that ba currently do. It would appear that an awful lot on here would be willing to leave their home countries, commands with relatively stable companies (easyjet etc.) and lives to join. I wouldn't do that to join Alitalia, Iberia, lufthansa etc. ( I am British). On the basis of simple supply and demand, the need to remain competitive, the fact we are dealing with greedy humans and finally with regards to BAs attitude towards unions of late ( which I agree with) are you so sure things will still stay so fine for the next 10, 20, 30 years of your careers. Things change.
It was inevitable. If anything Ba haven't been aggressive enough this time though they'll probably gather that from the union response.