Glad to see you mentioning neuroplasticity Bruce
I'm definitely of the opinion that neuroplasticity is the way we change our brains and hence our habits, personality, traits, etc... (
What Neuroplasticity can Teach us About Personal Growth )
The thing is, like Bruce alludes to, change isn't easy. And the bigger the change, the harder it is to do. I think just about any change, no matter how drastic, is possible, but you either have to be highly motivated by external factors or else have a lot of internal, self-propelled motivation to make those big changes happen.