You can't arbitrarily make assets. The total capital in the world grows but grows slowly. And doubly slowly for you if you are poor. I think Piketty wrote something about that.
For an example, I live off the profits of a SaaS business that I built myself. In addition to creating wealth for me, it is in fact an asset that I can sell if ever I want. It genuinely is "money" poofed into existence out of nowhere.
All we've actually done is add an extra zig in to the capital flow I described above. So before, we had Joe earning a dollar, using it to buy a donut from the grocer who puts it in to the bank. Now, Joe gives that dollar to me in exchange for my service, and I use it to buy that donut.
No central authority decided to increase the wealth supply. I did it myself.
In effect, we have.
I work, earn a dollar and put it in the bank... who lends it to a company who pays it to somebody else... who puts it in the bank...
There's orders of magnitude less pie to go around than has in fact gone around. That's essentially the basis for the world economy.