why do people feel the need to buy expensive cable

It is a little bit pessimistic picture. I try to stay optimistic.

Pessimist:  It is so bad it cannot be any worse
Optimist:    Yes, it can!  Yes, it can!

Inequality is indeed on the increase everywhere, and that is not good news for the mass of the population or for growth prospects. 

Even if you have
Even if you need
I don't mean to stare
We don't have to breed
We could plant a house
We could build a tree
I don't even care
We could have all three

So I disconnected all of my power cords and replaced them with the stock cords. I didn't tell my wife what I did, but asked her to listen to a couple of her favorite songs. Her reaction, what happened to the bass, his voice sounds dead, it doesn't sound good,  what did you do? Hearing improvements makes one a believer. 

Once in a great while I bother to read some of the drivel in the forums. I can truthfully say that I have never found anything useful here.
Willemj has a point. Years ago while I was at IIT in Chicago I majored briefly in Electrical Engineering. I did so only briefly as EE thought that knowing how to make a circuit that worked meant that further science to make a circuit that sounded better was irrelevant.

Shortly after that I went back to physics. EEs don't engage in science; they forsake it saying they know everything. I have a friend who is self taught and who has solved the problem of some frequencies getting through amplification faster than others. He has a focus control that makes everything else sound broken. I won't list his name as he will not bother with 1950s scientists.