When Steve jobs took out of the envelope Macbook Air, the world was interested in 13-inch devices. Lightweight, self-contained, small. But... small. They are not so comfortable working with spreadsheets, videos or websites to impose.
In the middle of the last decade, laptops have replaced the usual dekstop in the homes of consumers. At first they coexisted in the neighborhood, but over time the big box left position. Along with them went the monitors.