I think some very good points are made ehre , particularlyt he one that BA shoudl realy take notice if passengers actually quote the registration of the shabby 76 thats much discussed.
The point I would like to make is that while crew, airline employees , enthusiasts and other who read PPrune gnerally do understand that the state of the cabin does not reflect the state of the airframe engine avionics etc what about Joe/Jane public who often cannot tella A318 from an A380 since they only see the cabin. It IS REASONABLE for them to conclude that if the bits they can see are shabby, dirty , not working , then like most other things in life the bits they cannot see are actually worse. How many repeat pax have BA lost because most people equate shabby dirty plane with badly maintained plane.
My personal experience has been that BA are generally not good at looking after the cabins, a bit biased as much recent flying has been on LGW shorthaul which until recently as someone pointed out was entirely dependent on the most decrepit 733s and 734s around