Why do so many companies focus on nothing but profit? It just seems like that to me. It's like if something doesn't contribute to profit they will barely even consider it.
The purpose of a company is to make a profit (nonprofit orgs excluded obviously). Would you start a company and not expect to make more money than you spend?
Now if you're talking about extreme hoarding and not reinvesting profits into research and development, employees, or communities then I can sympathize with you somewhat, but ultimately it's up to the owners of the companies to do the right thing.
As for the money issue in general: I work to live, not the other way around. I'm happy if I have enough money to pay the bills, save a little for a rainy day, and have some fun in my off time. I'm not all that interested in a 7-figure salary as long as my expenses aren't that high
That's because we've gone commercial. You're 100% correct, in today's world, the diversity means that that example doesn't work. Hundreds of years ago everyone did similar things (farming, metals, etc.). The farmers needed metal horseshoes, the horseshoe makers needed food of all sorts. The farmer who farms vegetables needs meat, and vice versa. There's just too many things to do that there's not demand for everything.
Currency is not that recent of a development. Even the ancient Romans, having a pretty developed civilization, used a form of currency: salt. Salt was useful to everyone so it became a de-facto currency. Sal (latin for salt) is also the root of the word "salary"