Sometimes it's a lack of capacity for novel thinking. Sometimes it's fear caused by past trauma. Or it can be age. Or an inability to overcome habits. The list goes on, but the point is that I've had to work with or supervise employees (even in IT!) that didn't have a creative bone in their body. It wasn't a lack of motivation, it was usually something on the list above.
These people absolutely deserved the feeling of being useful, and those are the people I'm most concerned for in this new post-LLM world. The creative types will most likely be fine, but we have words to describe creativity as an acknowledgement that there can be an absence of creativity.