Following that logic, most doctors and lawyers are also interchangeable for the most part. The majority of work in those fields is applying what you've been taught and trying not to screw it up.
And of course there are exceptions, but from what I've seen it seems like there are more opportunities for programmers to bring personal creativity to their work than doctors and lawyers, just because the field is less established and there are more open questions.
Sure, they are. That's the way hospitals are managed here nowadays - you make an appointment with a doctor with specialization xyz, and you don't know until you show up who's going to be there. They read through your medical history a few minutes before they call you in, and that's that. Centralized medical history tracking through automation is quickly making being a doctor a lot more routine than most doctors would like it to be.
And of course there are exceptions, but from what I've seen it seems like there are more opportunities for programmers to bring personal creativity to their work than doctors and lawyers, just because the field is less established and there are more open questions.