Obviously that depends on whether training and schooling is easily and cheaply available or not. In the US this might surely create a problem for the poor, but

Obviously that depends on whether training and schooling is easily and cheaply available or not. In the US this might surely create a problem for the poor, but in e.g. Nordic countries (I am from Norway) there is usually massive economic support available for retraining, school, university etc, so this isn't really an issue. As long as getting into a school isn't a high barrier, licensing could be positive in that it keeps a certain quality in a profession. Quite to the contrary I think many problems in American society is caused by too lax standards. E.g. Prison guards and police in Norway receive years of training compared to weeks or months in the US. A lot of that is about deescalating situations, understanding mental illnesses, negotiating etc. E.g. a Norwegian prison guard is more like a social worker than a gorilla with a big stick. A lot of issues are connected and can't be solved in isolation. E.g. why are health care so expensive in the US? One factor is that many health care professionals have a high wage. Why do they have such a high wage in the US compare to many other countries? A common tradeoff is that higher risks require higher rewards. You don't buy high risk stocks with low potential for return. Nobody will risk getting into massive debt for medical school in the US without the potential for a big reward. Thus the lack of cheap/free college education in the US also helps drive up health care costs. So when it comes to poor people, licensing, education, you have to look at the whole "ecosystem".