This is all fair and tempers my interpretation of your original post. Some people do get stuck, and members of echo chambers are a good example. I think this observation is likely a snapshot of people who usually do move forward, but take a bit of a pause as they indulge. Another example would be people who just don't care, who found a reasonable 9-5 "job" and aren't very interested in seeing it as more than that. They often have to be pushed hard to advance their skills. Thanks for the thoughtful reply.