Tolerance for rudeness
really depends on the business, the town, the country, culture, and many other variables. But it's not dependent on the decade we live in. I've worked retail and many of my friends work retail. Most feel perfectly free to correct customers. I've seen a cashier give a customer a piece of her mind for not putting his empty cart away, leaving it to block the aisle. And that was last year!
If you break something in a store around here, you'd better believe you're paying for it.
So I'm sorry your husband isn't getting decent support from his management, and I'm sorry to hear that his business caters to rude people. But it's not like that everywhere. Remember - "the customer is always right" is a phrase that's been making retail worker's lives miserable since the late 19th century!
You guys might both enjoy these sites:
http://notalwaysright.com/ (funny stories about badly behaved customers.) and
http://notalwaysworking.com/ (funny stories about badly behaved staff).