I share your theory. I understand it best in the converse, i.e., we can delude ourselves into thinking we will never be able to understand X or do Y. Not that many can personally identify with the experience, but a huge part of why people think they are "bad at math" is because they tell themselves so. They expect it based on stories they hear from others and then they reinforce it by getting nervous in critical situations and getting flustered. It is the same with positive change -- after a certain point you have to come to terms with what you have been telling yourself about your downsides and how arbitrary and mean that is, and then you can find some distance from that characterization of yourself and begin to work on a new one (which should be expected to be ultimately supplanted by the next, etc.).