I write software for a living. People come to me to write software for them. Why?
Because I write software at a lower cost then they do, I'm more efficient. They are not software engineers, but a hospital for instance and their core business is operating on people.
Now, when the hospital hires me, do I get richer at their expense? Not really, because the hospital could have done it themselves at higher cost. So I'm saving the hospital money, we are both better off.
Are you really that dense? I'm not talking about the hospital getting poorer because it pays you. I'm talking about the money that's spent on you that isn't going to be spent on buying beds, medical devices, as well as paying doctors, nurses, and candystripers. It's also money that can't be earned by their internal IT people, if they have such a staff.
If this hospital runs great as a result of your software, that means that they'll be getting more business and making more money at the expense of another hospital.
There's only a fixed amount of wealth in the world. Sure, countries can print money all they want if they run out, but the value of that currency drops relative to other currencies.
Again, unless you can dig wealth straight out of the ground, all consumerism does is shuffle money around.
The idea that capitalism can cause all boats to float is a fallacy. The average standard of living of society as a whole has increased due to advancement of science and technology, although you want to give credit to capitalism for that LOL, but standard of living is not wealth. Wealth is not measured as an absolute value. It's relative.