I certainly hope you do it that way. Do any users these days keep communal files? I may be misunderstanding you. And I don’t understand how this saves CPU? You mention CPU many times.
In the old fashioned days, the lines were more divided.
Writing: maybe first on piano/guitar. Then composing…writing all the parts.
Tracking
Mixing
Mastering
Producer comes in somewhere between writing and tracking.
Mixing: My opinion of a good mix engineer is one who is able to use words to convey descriptions of sounds so everyone is on the same page. That is a skill, and too many times I think both client and engineer are bluffing with each other in communications. To this day, I have a difficult time communicating words to represent sound, mood, etc
A good mix engineer goes far beyond what most prosumers on a DAW believe they do. For example they obtains the majority of dB’s that are often wrongly blamed on the ME. And they go beyond typical methods of compression/limiting. They, as well as the producer, know fusion. What instruments or sounds work together so 1+1=3, as well as 1+1=-3 that causes problems.
The mix engineeer/ME relationship should be an experienced relationship. At mastering, the ME can then focus on cohesiveness with tracks, slight volume adjustments, fresh ears, in a sonically built environment, and any technical errors overlooked.
So you are asking for workflow that imitates this process?
Doing pop, I have a master DAW template, that is quite large. I keep songs in different folder stages ranging from ideas/concepts, building, and finalizing. Somewhere in the building stage, 95% of my template is deleted as it’s not needed. If I didn’t do that, eventually because of adding stuff, I would choke my PC.
Since you mention CPU so often, I will stop. CPU should not be in the equation of workflow at all. Sure you can choke it by improperly used plugs. I’m confident you can further elaborate.