Oh yes, I too remember the days when BA offered a wide range of services to Australia and New Zealand alongside Qantas.
I think the first challenger in the 1970s was Singapore Airlines who saw the potential of the route and used the lure of Singapore Girl to draw away business. Others saw it worked and followed suit and with a lower cost base they were able to offer very favourable deals.
Of course things have changed now so much. The end of the joint service agreement with Qantas really has spelt the end for BA who will no doubt soldier on bravely for another year or so and of course Singapore Airlines and other South East Asian partners are feeling the chill of the success of the Gulf carriers.
I wonder where the challenges will come from next.