"Smart" is used to define good decision making. Making good decisions is very hard when the marginal consequences of bad decisions fall on someone else. It's always been harder to make good decisions when you live in a protected environment and/or have access to easy credit - either through the mechanism of a VISA card or a global unregulated financial market.
It's the same for CEO's of global organizations, bottom of the pyramid high school kids and everyone in between. Once you get appropriate feedback, you don't have to be "smart" to make better decisions. All you need is a modicum of common sense and empathy. That's why tipping point change in "smart" is plausible.
Besides, "stupidity" probably has a normal distribution at all levels of the pyramid. No one group, either CEO's of globals, high school kids or printing salesman have a corner on "stupidity."