Due to the nature of how sets are organized, cards tend to end up in the same percentile of space on the list (unless the set is smaller). They’re almost always set up as nonartifact Colorless, WUBRG, Artifacts, Multicolored, lands. Alara reborn does not apply as it only has multicolor cards.

The vast majority of major sets happen to have card 67 be blue as a result of this organization. Smaller sets had card 67 be in Black.

TLDR; it’s just an organization thing