That's the maintenance of coach that has made things worse otherwise coaches are 8/10/12 years old only. Just check out manufacturing year of any garib rath. NR maintenance is worse and that has made coaches bad.
Regarding shelling out extra money, everybody might not be fortunate enough. So it's not a good idea to compare everything through a single weighing machine.
At present we have 2006 made LHB coaches also, but is still good because their maintenance have been proper.