The home smart speaker market didn't even exist just a few short years ago, but it's taking the world by storm. It has since been joined by sibling products -- the smaller Echo Dot and the wireless Tap -- with Alexa at the heart of each one. Consumer Intelligence Research Partners (CIRP) reports that in just two short years after its introduction, Amazon has sold an estimated 8.2 million devices, and was one of the company's top selling items over the holidays. While competition in the field is intensifying, it may be difficult for similar products to overcome Amazon's early lead. Here are four reasons why Amazon could come out on top.