That's a good point. Perhaps the decline of work ethics reset every time hard times roll around. If there is less to go around, people have to work harder just to maintain. Therefore any generations growing up during wartime or depression/recession may return to a previous level of motivation, and as a result of themselves going without, spoil their children in return, starting another cycle of complaints about spoiled children.
I many ways, nagging guilt can be a strong motivator for spoiling children. Guilt for leaving behind a world that seems worse off than when you entered it. Stop doing that! The younger generation has to understand that never before humankind has had so many possibilities.
At 40, I'm surrounded by Generation "Me" kids from friends and siblings and in my view the main motivator is laziness. The problem is the spoiled kids of today are being raised by spoiled kids. Our generation started the sense of entitlement and it shows in the parenting style. Generation X is used to having it all and having it easy. Actual quote from a thirty-something mother the other day: "I always let them have their way because their whining gives me a headache".
and their parents caused the great depression of the 30s ...