I think it's an ego-defense mechanism.
I found your thread through Google, because I was just thinking the same thing. I'm starting to believe the idea of identity is our brain's defense mechanism of keeping ourselves in our comfort zone, because it brings predictability and that brings safety. But we don't need safety anymore. The problem starts here because, no matter what you tell yourself, the part of the brain that strives for certainty will still fight for it and it'll remain, whether or not you take the journey.