You may know that intermittent rashes are always invisible in the presence of medical credentials.

Years ago I became suspicious of my Samsung Android device when I couldn't produce a reliable likeness of an allergy induced rash. No matter how I lit things, the photos were always "nicer" than what my eyes recorded live.

The incentives here are clear enough - people will prefer a phone whose camera gives them an impression of better skin, especially when the applied differences are extremely subtle and don't scream airbrush. If brand-x were the only one to allow "real skin" into the gallery viewer, people and photos would soon be decried as showing 'x-skin', which would be considered gross. Heaven help you if you ever managed to get close to a mirror or another human.

To this day I do not know whether it was my imagination or whether some inline processing effectively does or did perform micro airbrushing on things like this.

Whatever did or does happen, the incentive is evergreen - media capture must flatter the expectations of its authors, without getting caught in its sycophancy. All the while, capacity improves steadily.