Poverty is the default state of man. How do you think life for humans was ~100'000 years ago? Abject, helpless, hopeless poverty. No shelter, no highly probable sources of food, nothing to protect against weather, nothing to stop the person from getting eaten by a bear. All the scarcities you take for granted to be redistributed equally were even more unevenly distributed among people. Instead of asking "what causes poverty", ask "what leads to prosperity." Freedom of association and trade and allowing of capital accumulation is the only thing that leads to prosperity.

Look at Botswana for instance, that instead of adapting Marxism after the colonial powers left (like neighboring Zimbabwe), adopted market freedom / laissez faire = resulting in the GDP growing from $70 per year in 1966 to about 20000 today = excessively greater living standards for the individuals.

Obviously it also very much depends on how you define "poverty." Usually we automatically take, say, the bottom 10% in terms of income or wealth and label them "poor." With this definition we will always have poverty, since there will always be a "bottom 10%". With this we ignore that the bottom 10% have excessively better living standards than compared to 100 years ago, correlating with market freedom that has flourished in SPITE of the state.

And if you look at nations like India and Bangladesh, the reason for why people are poor is not capitalism, but rather a lack of freedom. The labor of people in failed socialist states are worth so little compared to people in nations where trade is free/freer because of tariffs, government licensing and restrictions on market freedom, which basically give certain international companies monopoly. Peoples labor in Bangladesh or other third-world nations, which are usually very authoritarian and government heavy, are worth only three dollars a day simply because company X pays for a license from the Bangladeshi government to be allowed to hire workers, which results in that nobody else can compete for the workers. So here you have a situation where company X has bribed the government to get special privileges and the exclusive monopoly access to these workers = the wages will remain low. Also lack of freedom of association is a problem, such as workers forming voluntary unions, which is outlawed in many of these nations and will result in heavy jail sentences.