Imagine that you had invented a thingamajig that was widely recognized to be of high quality and very useful. Soon, everyone was buying one and your hard-earned investment was paying off. The, suddenly or slowly, purchases started to drop and the money was only come in dribs and drabs. You’d reached the dreaded saturation point at which everyone who needed your fantastic thingamajig already had one and, since you had created something with such high quality, the only people who ever purchased another were those who had lost it somehow. At this point you have to invent something else that everybody is going to need if you want to continue to make money.
If, however, your invented doohickey had in it a joint that weakened and broke after 200 uses or if the outer covering of it could be redesigned to make the old one look so unfashionable as to be embarrassing, why you’d be back in business. The idea of planning for future failure, or engineering need for continuing purchases into a design, is termed planned obsolescence and was popularized as a concept in the 1950s by Brooks Steven.