A brief explanation why…
According to Android Inc. founder Andy Rubin, the software that became the company's Android smartphone OS was originally designed to be used in "smart cameras" but was later repurposed for handsets after it was realized that the market for digital cameras was waning. His original pitch to investors in April 2004 included a camera connected that would connect to a home computer (wired or wireless) that was connected to an Android datacenter.
Said to be Google's "best deal ever," the company bought Android in 2005 for an undisclosed price that is estimated to be $50 million (out of the company's total expenditure of $130 million for acquisitions that year). Following the buyout, Rubin became Google's senior vice president of mobile and digital content where he remained through March 2013 before moving on to other roles within the company and eventually leaving in October 2014 to start an incubator for hardware startups.
As of November 2016, Android was installed on 88% of the world's smartphones.