Sometimes things that may have been useful in the past become used for the benefits of others. Laws often are used to manipulating markets in order to keep competition from getting rid of a good gig people have. Take Child Labor laws:

In most countries, laws to protect children in the workplace began before there were laws governing working conditions for adults. Such laws reflected public concerns because of the special vulnerability of children, due to their inexperience, weaker bodies, and general helplessness against the power of adults. At one time, children were used for hard and dangerous work in coal mines, as well as working around factory machinery that could maim or kill a child who was not alert to the dangers. However, laws passed under one set of conditions often remain on the books long after the circumstances that gave rise to those laws have changed. As a twenty-first century observer noted: Child labor laws passed to protect children from dangerous factories now keep strapping teenagers out of air-conditioned offices.

Such results are not mere examples of irrationality. Like other laws, child labor laws were not only passed in response to a given constituency—humanitarian individuals and groups, in this case—but also developed new constituencies among those who found such laws useful to their own interests. Labor unions, for example, have long sought to keep children and adolescents out of the work force, where they would compete for jobs with the unions’ own members. Educators in general and teachers’ unions in particular likewise have a vested interest in keeping young people in school longer, where their attendance increases the demand for teachers and can be used politically to argue for larger expenditures on the school system. While keeping strapping teenagers from working in air-conditioned offices might seem irrational in terms of the original reasons for child labor laws advanced by the original humanitarian constituency, it is quite rational from the standpoint of the interests of these new constituencies. Whether it is rational from the standpoint of society as a whole to have so many young people denied legal ways to earn money, while illegal ways abound, is another question.

Sowell, Thomas. Basic Economics (Kindle Locations 4458-4476). Basic Books. Kindle Edition.