Around the year 2000, I realized that digital cameras would replace film-based cameras. What I did not realize was how low the price of these cameras would fall nor did I realize how cheaply it would be possible to produce a digital camera. I had thought that single-use cameras would be largely unaffected and would support film production for the foreseeable future. The prevalence of camera phones and the resulting low-priced components has clearly changed all that.
Have you ever wondered how a fully-functional digital camera can be sold for under $20? These two videos from the Khan Academy answer that question: