As manufacturing has moved from items with many components connected together with wires to more integrated designs, the concept of "replacement parts" has drifted out of use. A TV used to be a collection of little systems working together - a cathode ray tube, an electron gun, a phosphor screen, a channel knob, an antenna - to bring a picture to you. Now we have TVs that consist entirely of one integrated component with a plastic case around it. If it breaks, the only "replacement part" you can get to fix it is an entirely new television. Ditto for phones, except for replacement screens, every kitchen appliance made in the past decade and too many mass-market computers. If it breaks, you might as well buy a new one, because repairs cost just as much. When did we get this wasteful?
Mokalus of Borg
PS - Custom-made goods are even worse in this regard.
PPS - Unless they've been designed with common components.