The Vilna Gaon wasn’t, in his time, accepted as the top leader by all of Klal Yisroel, either. So I don’t see how today is any different than the time of the Gaon.
It has been far from uncommon for Klal Yisroel to have had one widely acknowledged leader of leaders. The Chofetz Chaim, who lived during the lifetime of some Yidden alive today, is another recent example.