I can imagine, in Trek's magical fantasy land (and don't pretend this stuff was ever consistent), a situation where Nero appearing in 2233 set off a chain of undone and alternate interferences, where people in the future weren't there to affect the past as they "should", leading to a different parallel past as well as a future.
I can also imagine that Discovery takes place in a post-Temporal War universe, which wasn't fixed as perfectly as Daniels and Archer thought at the end of "Storm Front". Maybe the "true" TOS world is out there somewhere with it's jelly bean buttons, paper printouts and bright jammies, or maybe the grimdark bluniverse is the shape of it now, the result of Future Guy, the Xindi, the Borg, the Sphere Builders, Vosk and god-knows-who-else sticking their fork in history.
It's fun to think about.
I can also imagine that Discovery takes place in a post-Temporal War universe, which wasn't fixed as perfectly as Daniels and Archer thought at the end of "Storm Front". Maybe the "true" TOS world is out there somewhere with it's jelly bean buttons, paper printouts and bright jammies, or maybe the grimdark bluniverse is the shape of it now, the result of Future Guy, the Xindi, the Borg, the Sphere Builders, Vosk and god-knows-who-else sticking their fork in history.
It's fun to think about.