The difficult thing with airline companies is that improvements are so expensive. In order to maintain costs reasonable, airlines keep using the same aircraft for a long time. Similar to a family keeping a car for quite a few years to get the mos that they can before they are able to afford an upgrade. Unlike with passenger automobils, airline companies are in a much smaller market so innovation and acceptance could possibly be post poned and lagging compared to the automobile industry level of sales of new cars.
Looking at the fleet ages of several airlines, it seem that the average age for an airplane is roughly 10 years. Some airplanes are even almost 20 years old.
Although it is not shocking that the airplanes remain well maintained and can fly for a long time, the addition of more nature friendly alternatives is promising for a brighter future.