For whoever is genuinely interested in helping the poor, it may be less useful to explore the causes of poverty, and instead analyse what causes wealth. It seems reasonable to me to assume that poverty, not wealth, is the baseline condition of life.
So poverty needs very little explanation; it is more of a default situation than a puzzle that needs to be solved.
If you identify the causes of wealth, then you can look at factors that hinder the creation and accumulation of wealth.
These hindrances are likely to include the prohibitive power of massive corporations that cripple small competitors; but I suspect that there would be few institutional obstructions other than this. The causes, and hindrances against the creation and accumulation of wealth, I think, will prove to have much more to do with individual characteristics, personalities, and family background, than with societal factors.