I went through my MM and found it interesting that out of the four fey I found (Dryad, Pixie, Satyr, Sprite), only the Dryad has Darkvision. So arguing that Elves have it because of their Fey connection isn't well supported. Since they do operate under twilight and moonlight conditions culturally, it makes sense for them to have something in game mechanics to compensate (i.e. Darkvision).
However, like a lot of you have mentioned house-ruling a return of Low-light Vision, I will probably give Elves and Forest Gnomes "Moonsight" (aka kind of like Low-light but it sounds more fantasy-ish). With Moonsight, the character can see in Dim light as if it were Bright light up. Moonsight does see in color, albeit slightly muted with a silvery edge, and it has normal range (normal vision distances). Elves and Forest Gnomes in Darkness cannot see and suffer from the condition as normal. Moonsight will not operate in magical Darkness.
Half-Elves do NOT have Darkvision or Moonsight. (Hey, they get enough IMO.)
Drow will retain Darkvision and as well as other Gnomes. Darkvision is mechanically RAW, but shows color that is tinged by heat (infrared) instead of just shades of gray.
In summary:
Dwarf: Darkvision
Halfling: Normal
Elf: Moonsight (Drow: Darkvision)
Human: Normal
Dragonborn: Darkvision
Half-Elf: Normal
Half-Orc: Darkvision
Gnome: Darkvision (Forest: Moonsight)
Tiefling: Darkvision
Pixie, Satyr, and Sprite have Moonsight as well.