I've come to realize people don't want stories, they want character sims. They want characters to act out their own personal vendettas or personalities irregardless if it makes sense for their direction or plot.
The thing about "not developing every character" is that stories need focus to be Stories. There will be a principle focus, theme, beat, while other things will have to be peripheral / supporting. If everything's given Equal Weight, then it's not really a story, but a simulation.