The world is finite. That's a fact. The universe is not. However, at the current time, we don't have a universe wide economy; we have an economy that is constrained by limited worldwide resources. Therefore, a way has to be followed to dole out those limited resources.

One idea floated around for the last hundred years or so is to evenly divide up those resources among everyone and have us all sit a round a fire signing folk songs. This ignores human nature and the facts that many people sing off key and burn the marshmallows.

Another idea floated around for several thousands of years is that we divide up the resources between the strongest among us and allow the weakest to be slaves, serfs, peasants etc. and allow the strongest to dole up rations.

yet another idea is that we allow everyone an equal starting chance for everyone to get a share of these resources. The harder they work, the more they help, and/or turn natural resources into bertter products( value) the more resources they are able to get and keep..

these ideas are known as
Marxism/socialism
feudalism/law of the jungle
capitalism/free market.

each has its drawbacks and benefits. None are the best answer but one is clearly better than the other two IMO