Things weren't also helped by the fact how the 2011 Japanese earthquake and tsunami kind of interfered with the storyline as well - datamining in 1.0 has uncovered how the story was going to continue post Futures' Perfect quest (the last available 'Path of the Twelve' main scenario quest in 1.0), where the player eventually ended up encountering Titan fighting the Company of Heroes - Leviathan's model was also found but had no story connected to him at that point.

So it's clear a lot of the abandoment of 1.0's original storyline was simply due to SE deciding a story featuring Primals that created earthquakes and tsunamis was understandably just a little too close to home at that point in time for Japanese players, and so were put aside, and eventually once Yoshi decided to replace 1.0 with '2.0' (ARR), it was ultimately abandoned, being kept aside for inclusion in ARR. Once the 'Seventh Umbral Era' events began in earnest, the old story just kind of became irrelevant, a legacy of the 'bad times' of 1.0's original direction, so no wonder it ended up being abandoned.