Part of the WoL's canonical power is attracting the right people, too. Your nation's leader chose you to be an envoy because they sensed that spark. You getting involved with the Scions as early as level 17, when you're still a weakling, is destiny turning its wheels. The story builds it up such that the WoL makes the connections and has greatness thrust upon them in a way that nobody else can.

In 1.0, the Path of the Twelve was Minfilia's organization, where everyone had The Echo. Presumably, most of them were killed during the Calamity, or went into hiding, or were later killed by the Garleans when Waking Sands was attacked. But the echo, while uncommon, is not super incredibly rare.