The bike comes from the achievement "A Complete History" which means that the only way they can make the bike more easily attainable is if they allow purchasing of the requisite field records. If it were a direct drop they could throw it into a moogle tomestone event, but otherwise there isn't a good way to do it.

The bike is honestly not worth the effort needed to get it 100%. It just turns into sunk cost fallacy to try to keep grinding for it unless someone decides they want to get good at doing duels, as that solves at least part of the problem. However, the duels are intentionally very difficult and/or time consuming in their own right, and require a lot of prep to even perform.

And FYI, it would be an act of god at this point if anyone has all the field records and doesn't duel. 4 star and up logs are no joke and it turns into a super high grind RNG fest no matter how you push it.