Money as I see it is a man made construct that is a tool for obvious needs and wants to be faciliated for all in the multitude of ways any given human will decide to use it.
As a theory ANYTHING is workable and will do it's intended purpose which of course rarely ever translates into high % success rate when applied in practice.
Capitalism and all other forms of economic systems with their respective socio-political dynamics/factors have flaws and none offer a totality of equitable good.
Equality and equity are often mistaken for the same thing in both directions where someone says they want equality but they actually want equity of opportunity/outcome.
Earth (as a resource) sans the national borders,corporate interests,racial and ethnic divisions,biases,prejudices and bigotries can sustain all with a certain standard of living.
Currently and for a LONG time the access to and use of all the important wealth and resources have been so vastly disparate that the extremes do enter into caricature.
All of the above I know men and women with intellect way above mine have done in depth anaylsis of the why hows and wherefores and reach various conclusions.
The human species collectively on earth has reached the point where powerful and far reaching factors have exerted themselves out to degrees that now despite there being few to no logical reasons for it - sufferings and pleasures of all manner occuring simultaneously.
The human nature/condition or whatever one wishes to label it as is why.
Hate,greed,envy and all the ugly traits of humankind have prevailed over the good,the kind,the sharing the beautiful traits humankind also possess.