The whole condition is related to a kind of mania that has taken over the world ever since cameras were invented, but more-so in the last decade or so, when people have been enabled to publish their pictures online and can also enjoy them without having to develop them.

not

it has to do more with availability of use. If everyone could afford a painter everyone will be getting selfies

Consider the social instinct, a value most of us share. It means that people feel that their life has meaning when they share it with other people, and they feel that their life lacks meaning when they fail to do so.

So there is no survival instinct because there is a teleological aspect to it but there is a social one. This is what we call intellectual dishonesty. Literally.

I tried to give some applications of the theory of use as they apply in everyday life, specifically to our own bodies. Our bodies, like everything else, must be given some use-value if they are to be invested with meaning.

It's bullshit. It is not your "theory of use". You take the dictionary meaning of the word "use" and spin the words around in order to say pretty much "water is wet and its meaning is humidity'.