Whenever anyone gets on me about how perncious a third party would be, I have one response: To Hades with a third party. We need a second one.
FWIW, I could give a rat's hairy hind end about the letter after someone's name. Party means bupkis anymore. Which also means, at least for me, that party loyalty is no reason to support, endorse, and/or vote for someone.
As for no "outsider", by that I guess you mean a party animal, being able to win....refer to my never say never comment :)
My point is that if one wants to run for President, they’re going to need some backing from the party establishment. Your example is best suited for those running in Congressional races.