I think that if you want to keep a customer then you're better off not swindling them.
It depends on what sorts of sales you're doing. If they only have to buy it once for it to be a victory, it plays out like the Box Office model for movies.
I don't know what Cain was selling, maybe this approach suited the industry (very well possible) where you just have to push through to the sale and you can wipe your hands clean. Or maybe the product just speaks for itself? lol
It was a market where people could have just as easily bought things of the same value from the neighboring stands. He was at the same markets every week, even with loyal customers coming back because they liked the cut of his jib instead of any real empathic connection.
When they could just go to other places nearby to get the same sort of stuff, or even go a little further away and get it even cheaper, his ability to do sales speaks for itself. He got there because he was able to appear to be giving them what they wanted more than anything, and he made them feel confident with not just the product, but the one selling it.
Selling "comfort" is not an empathy job in particular. The best ones tend to just be grade A sympathizers.
Obviously some psychological tricks are universally applicable but way too many guys go into business thinking they're on some Wolf Of Wallstreet shit and just go ahead and burn a few bridges and get a bad rep because of it.
Wolf of Wallstreet is the stock market, which is it's own can of worms.
After enough psych and graphic design classes, alongside being raised by an advertiser in California... it's more than apparent how depressingly based on bullshit that the best salesmanship tactics really are. Commercials don't aim to empathize, they aim to control, and a salesman isn't that different beyond the stimulus sources.
You ever watch the show Mad Men? They love discussing this stuff, such as if selling Cigarettes as "a death wish" would get better sales than saying it's healthy.
There's this gem of salesmanship:
Ę̵̚x̸͎̾i̴͚̽s̵̻͐t̷͐ͅe̷̯͠n̴̤̚t̵̻̅i̵͉̿a̴̮͊l̵͍̂ ̴̹̕D̵̤̀e̸͓͂t̵̢͂e̴͕̓c̸̗̄t̴̗̿ï̶̪v̷̲̍é̵͔