My thoughts, when asked for all the photos, it’s sometimes the client viewing all the photos (even the photographer’s rejects) as possessing an aesthetic quality that would surpass their own achievements.
This also depends on the type of client. Those who generally remember the days of film got used to the narrative that the photographer’s talent was what you were hiring and that this could be atomised.
A cost for the shoot and then prints from the negs. Any further prints meant negotiating with the photographer who retained the negs (his/her property) and would charge for reprints accordingly.
Digital presents a new schema regarding the physical assets and workflow which the customer, particularly in this ‘sharing-ecosystem’, wrestles with initially.
Perhaps, editing, not as a selection process, but often post-production, requires even greater clarification. The analogy I use as a film maker, and I’m aware of the difference, is for the client to either let me give then the completed film (edited and post) or the raw assets. I know which one they choose all the time. And yes I agree with you that, ‘My editing is part of my process, my product, and my style. It’s part of why you hired me’.