[TrainedMonkey]

You are correct that a larger sensor would capture more photons, however I think you are not comparing apples to apples. That picture is a snapshot with basically 0 visible light and was made possible by capturing a lot of channels and running a remarkable software enhancement. AFAIK, there is no API to do anything like that with uploaded raw picture (0). So to get a similar quality picture with a larger sensor you will need a long exposure time... and an average human subject shivering in a cold environment will come out way blurrier.

Good portraits are usually made by excellent lightning conditions. As a portrait this picture is average, but when you take conditions in the account the result is quite amazing.

(0) That is an assumption I am making which might be wrong. You could also definitely do this by hand by investing 100-1000x more time.