So, I think I agree with you, in general, that people can be better suited to green-field or maintenance, both from a skillset and personality perspective. But I also think good, active maintenance can have a lot of creativity and require, as you say, envisioning what doesn't exist.
If we're just talking about bug fixes and level-2 support or something, sure, that's mostly about attention to detail, etc. However, maintenance is much more than that, in my experience.
Maintenance involves keeping a system up to date and functioning in the face of changing business requirements. So, you have a new customer come onto the system or a department wants to change a business process, and now you need to change the system. What was once a single implementation of some feature now makes more sense as an abstraction with extensibility points. Or maybe just the system has more data than anticipated, and a good developer might realize that instead of putting a bandaid on the Postgres search, it's better to integrate a dedicated search solution like Elastic.
The point is that software is never done, as long as it's being used. Drawing a line between development and maintenance is often just an arbitrary distinction.