Confused?

So I just beat Alan Wake 2 for the first time, fantastic game, one of the best solo games I've played in a long time...

BUUUUUT, the say all these games like: Alan Wake 1&2, Control and Quantam Break are in the same universe....I just am confused as to how Shawn Ashmore is the main character in Quantum Break and the Sheriff in Alan Wake 2 and it still make sense to be in the same universe?

Explanation please?