Most of the really good people I know who have a PhD realize that the PhD was not worth the effort and would have been better off starting gainful employment with a master's degree. But at least they/we were smart enough to learn that. When we hear of someone with two PhDs we know that that idiot was too stupid to learn after the first one. Any more and you should be committed to a lunatic asylum.
Hint - a PhD is an official certification that you have proven you can do independent research. A second certification is unnecessary. Want to go research something else - crack the books, go to a research library and start learning and doing.
That's so funny. I don't remember reading about anyone with two PhDs. Who would fund that?