Is it possible to support oneself as a lifelong graduate student?
Why would you want to get multiple PhD degrees when the first one is all you need to do research for life? Much of the point of the degree is a certification of your ability to do independent research. After you've done that, you can get a job where you do research all day long! Many people get a professor's job where there are other duties, but plenty of people get jobs doing just research at government labs or non-teaching academic departments (like me!).