One of the fun things in the airline business was rumors. Everybody, of course, wanted to fly something bigger, and there was always a rumor of bigger and better. Great fun, and rarely important or prescient.
Then one day a first officer came on board and said " we are getting 757s!". For us, that was a giant step up. They actually happened. Then one day another first officer showed up saying we were getting fifty Airbus airplanes. Well, I knew that couldn't be true, and six months later I was in Airbus school. Should I tell you about the 747 rumor?
My point - other than that rumors can be fun if not productive - is that every once in a while a rumor can come true.
As to the expense of overhauling a Big Boy or Allegheny? Chicken feed to those who can do it. This morning's LA Times talked about a baseball team for two billion bucks, and two pitchers for 200 million. Just depends on your priorities - for those guys, money is not the point.