This chart you shared shows GDP Per Capita which usually always increases because most countries today use fiat currency economic systems where central banks and regular banks increase the money supply over time, so more money in circulation means some people will earn more money. But as you already know from this chart you shared earlier the more money is created the more it drops in value

The math I am talking about is this math in the chart below

As you can see, as some people are accumulating wealth in an economy other people are losing wealth, because the money is moving from person to person.

I assure you my intention is not to misinform you or lie to you, there is nothing in it for me, I am simply telling you how the economy works mathematically. It is the same in all countries and all economies. The only thing that changes between countries are laws/policies, are they more capitalist, more socialist, more communist, no laws at all, etc, etc... This is what changes human behavior and determines how they can earn, spend and/or accumulate currency depending on what country you live in.

That is why I made my original point about Thatcher's quote being false, there is always money in every economy, you can never run out of other peoples money, you can be rich one day and poor the next, the money did not run out it simply moved to another person.

I have explained this to you the best that I can, I encourage you to study the economies of different countries and how money flows through the economy, this is an excellent video from an economist who is very knowledgeable about the global economy and economic history https://youtu.be/ynbgMKclWWc
But don't just take his word for it, if you want to understand a topic you have to be willing to learn from many different people who have studies that topic and determine for yourself what makes sense...