If I bump the saturation or touch the contrast in LR, how is that different from choosing Velvia film? Again, both are choices which we must make as part of a creative process.
I think this is the essence of the OP's question. And I don't have an answer to that. I don't know if anyone has the authority, moral standing or sheer personality cult mass within modern photography to proclaim where one stops (image creation) and another begins (processing/alteration).
If I'm shooting film and move the lens to create motion blur, I am purposefully abstracting the image. Do we consider that image creation or image alteration?
Again, you have struck to the core of the question. Is it image creation because it was created as an inherent part of the way the image was formed? Does it become processing/alteration if you augment the blur in Photoshop to accentuate the subject? These are nuances that did exist in the analog world if you sought them out, but are part-and-parcel of the digital realm.
Should we consider it to be an authentic representation of a scene simply because it was done using film?
It has been so long since I've used film, I can barely remember what it was like. I started with digital processing in the mid-80s, and I can barely remember last week.
But seriously, I don't subscribe to any of the tribal stuff between film vs. digital. I don't see any inherent superiority or inferiority in any method to creating the image.
Yes, I understand the romantic nature of film and the tactile feel of the paper, the smell of the chemicals, yada, yada, yada. Believe me, every time I smell certain things I am transported back, but mostly to memories of breathing waaaay too much Cibachrome bleach.
But, in my experience, the client really doesn't care how you created the image, only that you created an image that met their needs. In that regard, none of our esoteric conversation of creation vs. processing/alteration matters, but to those of us involved in the process I think the OPs questions strike to the heart of understanding how we personally achieve the goal of the creation, and where various parts of that creative process reside.
Good talk. Much better than talking about gear.
Hear, hear.