Is it possible to support oneself as a lifelong graduate student? I don't care much for being rich. I don't mind a modest life if I can just do research in the field I love.

Thus I am curious to know if it is possible to make a living just by studying. (Suppose I could hypothetically get funding for every Master or PhD program). Is there an age limit or a limit to the number of PhD degrees that I could get? Are there any other reasons that prevent this?
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!).