When beef prices rise we buy less. When interest rates rise we take out fewer mortgages. After all if people didn't respond that way sellers could charge any price they wanted and we'd still buy it. Labor services are no different. Among those substitutes are automation, moving to a lower wage country and customer self-service.
Low wages are more a result of people being under productive rather than underpaid.
They simply do not have the skills to produce and do things their fellow man highly values. Seldom do we find poor highly productive individuals or nations. Those who earn low wages tend to have low skills and education. Most employers would see that as a losing economic proposition and wouldn't hire such a worker. Therefore, a major impact of the minimum wage law is to discriminate against the employment of low skilled workers.