I can understand why you would think about it in that way, but the size of the lens isn't the reason why the dust doesn't matter. Instead, it's the object distance from the lens and aperture. If you are focusing on an object that is 10 meters away, the dust spec which is 1mm away from the lens is imperceptible because it blurs out of focus. It is physically (and I mean actually from a physics perspective) impossibly for the iPhone camera lens to focus on an object that is 1mm away from it. That is why unless you have tons of dust that is covering most of the sensor, a few specs are invisible and have no impact on image quality in a fixed large aperture lens (like yours). That is what the author of that article was trying to prove - dust doesn't matter and even objects as large as a torn piece of paper don't matter unless it's significantly covering a good portion of the lens and shooting with an f stop of 1/11 (which is impossible on your lens). You can't tell me your dust in relation to your lens size is equivalent to 3/8" pieces of paper on a DSLR lens (which still didn't impact image quality with a large aperture).
Exchange your phone if you must, but I hope you have a better understanding of the physics behind lenses and why the dust is only a cosmetic problem.