I could see a split model emerge where you can buy ultra cheap fares and then choose to bolt on meals etc if you want. This may appeal to very cost concious travellers for whom £20-£30 may be a not insubstantial sum.
Similarly, you could create a menu of options, ranging from the ultra cheap 'seat and nothing' through to 'Y' standard as we have now, through to 'Y' enhanced where you could pay for meals (as now) but also other bolt ons like access to the lounge or access to priority security (doesnt Emirates do this). Create an economy plus service, and then let people choose between what they want to pay for, but then make clear that BA does a combination 'luxury' for WTP+ and above, and very very basic galley slave class in the back.
To combine two very different business models in one plane could be interesting though!