By 2005 Google had such an insurmountable edge that there was barely a discussion. Microsoft started development in what would become Bing before that, and desp

By 2005 Google had such an insurmountable edge that there was barely a discussion. Microsoft started development in what would become Bing before that, and despite all their efforts were never really able to catch up to anything that Google was doing. Yes, click data helps but really only at the head, where Google already excelled. On the tail the increasing dependence on click data (and later on machine learning and an increased focus on user-specific results) has steadily made Google worse and worse, and Google's supremacy has really only lasted this long because of their page quality measures, which is still a huge problem even now on Bing.