Because human beings have evolved so far that he richest amongst us have time and money to sit and navel gaze. Angst, worry and wish...
We can't go out. Space is still too far away, though very recent events have changed that a little bit.
So we look inwards. We fidgit, faddle around and decide that we are what we feel. We have spent decades discussing how much feelings, a sense of inner being, effects us on a daily basis alongside a lessening of the daily grind of hard work, the improvement of our living standards. We don't just live to work to exist any more.
So now our 'feelz' have currency.
Anyone who has read a lot of sci fi from 1870s onwards will know what happens in indolent societies, societies with a lot of leisure, technology, separation of generationa. This isn't much different from some Jules Verne, H G Wells, Robert Heinlein, Asimov, Doc Smith etc.