The Watchtower has from its inception taught a chronology-based theology. Now that we're so far from 1914, it would seem they would want to back off their date-based theology. But we see it still churns up in their literature time and again.
One of their base doctrines, used to establish their "choosing" as God's organization, is that in 1918-19 God and/or Jesus came to inspect mankind's religions to choose which one would be his representative for the last days. Voila, the Watchtower (with all it's "old light") was chosen as God's instrument of truth, as per Watchtower doctrine.
Now if you were to take away the 1914 date (which has been repeatedly proven meaningless on this forum because the 607 BCE date for the fall of Jerusalem is wrong), then the 1918-19 date loses its significance. And then God and/or Jesus didn't really crown the "Bible Students" later known as Jehovah's Witnesses as his official message-bearer to mankind.