That isn't unique to Computer Science or Programming. I've worked with engineers, accountants, project managers, and many trades people that never touch their area of expertise outside of the classroom or the office. No venturing outside the curriculum or the self improvement on personal time. For most of them their job is just a job and that is enough for them.

I think what is amazing about programming is that so many people are able to get jobs without degrees. There is a general consensus that self taught developers can be as good or better than formally taught ones. I haven't seen this in other fields until you get to senior leadership. Sure, areas like law and accounting require a formalized foundation that are hard to get outside of degrees but trades is an area with a lot of room for self-development yet there is little respect for those without certificates. Sure you can make the argument of insurance needs but that just raises the question of why contracted developers don't need to be bonded.