I think there's a difference between keeping a guy on your team for years and years hoping he'll improve and acquiring a player who couldn't make it happen on his old team.
Who's to say Newton was on the right team to succeed? I know that point is kind of silly considering he's 31, but crazier things have happened.
Also, Newton may not have a ring, but his overall body of work is as good as some QBs who do have a ring. Maybe those QBs (like Flacco, Eli, Foles) wouldn't be the answer either, but it seems pretty fallacious to say Newton hasn't proven *anything*. Dude won MVP.
We aren't talking about a career where he kept getting the starting job out of indifference/complacency. It's a guy who's been close to the pinnacle but for a few different converging reasons didn't get all the way there.
I don't think he's our probable answer, especially long term. I feel that way about Stidham as well. But to frame this as the QB equivalent of hiring Jeff Fisher is dishonest.