Why does Holden refuse to go into the museum?

Holden's whole life has changed since the last time he went in the museum with his class. He is not a little kid anymore, D.B. moveed away, Phoebe is older, and Allie is gone. Holden has been sent to private school after boarding school and has lost his faith in people, but the museum is the same for him. Nothing should be moved or added, the indians should be canoeing and the eskimo should be fishing. If Holedn were to go inside the museum and it were different, he wouldn't know how to react. After all these years, and memories of going into that museum every Saturday,  he doesn't want it to change. Holden wants one thing after all these to be the same. His memories of the musuem include Allie being alive and D.B. being there, and that is what he wants. Holden wants to go back in time and spend every second with his family before his world is torn apart by disease.