There are several types of unemployment

• Frictional Unemployment, in which the the unemployed person is between jobs. They may have left their previous job because they were not happy with it, and are likely to find something else in the near future.
• Involuntary Unemployment, in which the unemployed want to work, but are unable to find work.
• Voluntary Unemployment, in which the unemployed choose to be unemployed.

A high frictional unemployment is quite high in wealthy societies, are of no great concern.

Involuntary unemployment is caused by minimum wage levels being higher than a worker's productivity. This is turn is partly caused by unionism, and partly by minimum wages. Every employer who is thinking of employing someone looks at that person and asks the question: "is the money I can make from employing that person higher than the cost of employing them?". If the answer is no, they don't get employed. Everyone has some level of productivity. Someone who is aggressive, unintelligent and uneducated, may have a low productivity, but it is usually still positive. They could be employed for menial tasks which do not require punctuality or acceptance of a high degree of responsibility. However, if this (net) productivity isn't higher than the minimum wage, they are stuck with being unemployed.

Voluntary unemployment is caused by welfare. Some people prefer to enjoy 24 hours a day of leisure rather than to get a job. Welfare makes that possible. The higher the welfare payments the more people will choose welfare over work.

If there are no minimum wages, and no welfare, there is no involuntary unemployment.

We fix minimum wages and conditions to a level which is higher than someone's productivity, then they will simply not be employed. Whether the employer 'could afford' to employ them and make a loss is irrelevant in a free market, and command economies have been known to fail.