This really is the key to the entire thing. Brilliant observation and well-put.
You have to find a way to separate the romantic notions of what it means to be a writer from what you’re actually writing and saying. Don’t get rid of it entirely–because you’ll need it to make it breathe and to make it uniquely yours–but if you want to know what it is you’re saying with your story, you need to put away the fantasy.
That’s the only way to see your work objectively–but it’s generally not the reason why people become writers.
You’re really just substituting the arguments that go on in your head with plot, character, theme, and genre. A story is one thing–one argument–and the Throughlines are different points-of-view on the singular thing.
Conceptually, it’s really hard for writers to empathize with because it objectifies the magic.
The four throughlines are not real “things”, the four throughlines do not make an argument. The argument makes the Four Throughlines.