Generally, they are university professors, and some have other legitimate occupations. European countries and the Royal Academy of Sciences supported them. Others don't have the above means to make a living when they are not famous, so they can make a living by the above means after they become famous. People only think about philosophy of science when they are full.

What you said is useful and useless. From an economic point of view, most people think that it is useless to do things that can't make money, so it's just a difference in attitude and concept of life. For them, it is most useful to engage in their favorite occupation. As far as society is concerned, the development of philosophy of science has promoted social development and social progress.