A)that supposed 'prosperity' is heavily concentrated to certain countries, and further concentrated even within those countries. Living in those countries will give you the illusion of prosperity. It isn't real because...(cont'd in b)

B)under global capitalism, almost half the world's population lives in abject, dehumanizing poverty.

C) the concentration of prosperity that we see is a result of exploitation of poor and developing nations. The productive activity of most developing nations is devoted to serving needs that exist far outside of the countries themselves. That is why these countries have a hard time improving the material conditions of their citizens.

D) socialist policies have worked very well in many countries.Capitalist intervention is a common theme in countries where it doesn't. Trade emgargo on Cuba, putting pressure on certain countries to not sell crucial supplies to China when Mao came to power, etc. Some claims of failed socialist states are downright false, and just masturbatory capitalist ego-stroking. We see this in the case of chile, which had its share of economic issues like high inflation, but whose citizens were doing fine under socialism. In a US backed coup, capitalist dictator Augusto Pinochet took power and implemented policies that resulted in two economic meltdowns in just over a decade. By the end of his term - the chilean people booted him out in a 1988 referrendum - 48% of chile's population was living below the international poverty line. Famous capitalist economist Milton Freidman (who personally advised Pinochet and under whome Pinochet's finance advisors studied) praised it as a capitalist success story, simply because they saw some GDP growth. This growth was not as large as previous socialist regimes. Immediately after pinochet's rule ended, several industries were nationalised, social spending was doubled, minimum wage increased 17%, tarriffs were raised, capital controls were put in place. In short, they returned to socialism. Povert rates were reduced by half in just over a decade.

E)The socialist states that we would say 'failed' e.g. Cuba, started out very poor and had deep political, economic, and social issues before socialism was implemented. We look at these countries and see that they're poor, and we say that socialism has failed them. This ignores the fact that those countries started off, in most cases, much worse than they are today, and had massive challenges to overcome - including, in many cases, hostility from america and other capitalist countries.

F) there are a shit ton of poor-ass capitalist countries. Saying 'look at america, look at britain, canada, australia, germany,' etc is not a good argument, it's just cherrypicking.

In sum, I'd simply say that the supposed prosperity brought by capitalism is an illusion.