The Shining (film itself)

[whoisquilty]

Jack Torrence has become part of the Overlook. He's not reincarnated. He's become part of the "crowd" of ghosts that inhabit the Overlook. There is talk all the way throughout the film from the ghosts about him joining them or that certain things aren't a matter that concern him...yet.

The significance of the 1921 date is to tie the party scenes together with the end of the film. Jack has become part of the Jazz Age party that is forever going on at the Overlook.

Now, let's try to explain the guy in the dog suit giving the other guy a blow job on the bed...