Great question.
IMO...it has a lot to do w/ the era. 20yr ago people played for a couple of bucks for social reasons.
Now, I go to the pool room and don't see a penny bet while all the tables are going.
Ah, so by non-gamblers they meant people like me who play for $5-10 a game but usually not much more. Yeah, these days, a non-gambler is someone who won't even play for a beer. When I ask people in bars to play for $5, I often get a look from them like I've said something very inappropriate and antisocial. It doesn't take long for word to get around to the other patrons that we have a "pool hustler". Ha! I'm like a SL6 in APA 8-ball. Not exactly a world beater. So when I do finally find someone who will play for $5, I don't even have to like it.
It got me thinking, maybe my approach leaves something to be desired. Still hoping to learn what made Ferber and Pete Horn so good at getting people to bet.