Sorta? For one, you don't always have to do full site optimization for this problem. As such, the "N" you are working over is going to be limited to the number of breaks within a section you are looking at. And you can probably divide work across the sections quite liberally on a page.

Yes, there can be edge cases where optimizing one section causes another section to be resized. My gut is that that is the exception, not the norm. More, for most of the resizes that will lead folks to do, it will largely result in a "card" being moved up/down in such a way that the contents of that card do not need to be re-optimized.

Yes, you could make this even harder by optimizing what the width of a section should be and flowing another section around it. But how many sites actually do something like that?