Hi everyone! I was looking up something else on google and saw this thread and as a professional photographer I wanted to offer up an explanation. Before your camera takes a picture, it only needs to offer up a preview. The preview image is horribly noise ridden and only around 3 megapixels, so it doesn't matter. It looks great on your screen because you can't zoom in on it and the camera can crank it's ISO (like film on old cameras) to offer up a reasonable preview. BUT then when it takes a picture, image quality is a priority. So it will lower the ISO as low as it can so you're happy with your low light pictures, or else people will complain that they just have a noisy mess. The big limitation here is the fact that camera phones are typically hand held, so the camera can't leave its shutter open long enough to collect the amount of light required for low light shooting. So its back is up against the wall, it can't leave the shutter open or your pictures will be motion blurry/streaky and it can't crank the ISO because they'll be so noisy/grainy that you'll be disappointed. So it does the best with what it can. Phones are compromised compared to a dedicated stand alone camera system that has better high ISO performance, has optical image stabilization for night hand holding, and fast F stop lenses to let in all the light that it can. Your phone might offer you up a good preview with a decent exposure that it can't actually execute.
Hope this helps. It doesn't really solve anything for you guys, just wanted to explain the physics behind it.