Sounds like a lot of work for something which wouldn’t produce that good of a result. If you ever tried to take a colour from a picture with the eyedropper tool, you quickly realise what you see as one colour is in fact disparate number of pixels and it can be quite hard to get the exact thing you want. So right there you find the initial hurdle of finding and mapping the colour to change. Finding the edges would also be a problem.

Not to mention every screen is different, so whatever changes you’re doing, even if they looked right to you in the moment, would be useless when you sent your image to your computer for further processing.

Oh, and our eyes can perceive it differently too. So now you’re doing a ton of work to badly change the colours of an image so they look maybe a bit closer to reality for a single person on a single device.