Airlines which operated young aircraft, emphasise this in their advertising. Pictures of the interior are shown and features such as wifi and inflight entertainment highlighted.
Increased passenger comfort from a lower pressurisation level and greater humidity, with less noise and vibration were a major selling point for the B787.
Passengers willing to spend a bit more are likely to respond by purchasing tickets based on the experience rather than the price.
Airlines operating 25 year old B767s and MD80s concentrate on other aspects such as price or a comprehensive route network.
Low cost airlines prefer newer aircraft from the efficiency and reliability point of view, passenger experience is well down the list and little money is spent in this area, the desire being to keep costs as low as possible.