Red, I'm glad someone besides me enjoyed my post. I try!
I grew up with a father who shot an M12 through the 50's, 60's 70's and 80's. He started me with his M12 in 16 gauge. Then he bought me a Wingmaster for Christmas one year when I was about 20. I shot that almost exclusively for the next 25 years. But around when I was 45, I started to notice O/U and SxS, particularly vintage SxS. And after 30 years of hunting, it was a revelation to see and feel the quality in those guns compared to what I was used to. The handling of a well proportioned, well made, 6 pound 16 gauge SxS just can't be beat. And, importantly, at that age, I had the disposable income to go out and buy what I wanted (within reason). I find the other guys I have met who are interested in vintage SxS found their way to it in a similar fashion. Not too many 20 year olds, scraping together enough money for rent each month, are lusting after some grampa gun. But they'll come around in time.
There is a reason that new shotguns that sell for $100,000 are almost all a particular configuration, SxS. It's kind of like why all serious exotic sports cars are mid engine. At some point, when you want and can afford the very best there is, there is a fundamental structure as to what that "best" is.