What makes you think that the folks who dropped out would be affected by that graph?
Assuming that someone does something because they're ignorant is almost always a mistake.
Example - smokers know that smoking is bad for them and they knew it long before the warning campaigns. (The phrase "cancer sticks" is quite old.) If you don't understand that they smoke because smoking is better for them than doing without, you can't possibly help them.
Cigarettes are chemically addictive, so analogies to most other behaviours are weak.
Actually, almost all of them are.
> They don't want to be high-school dropouts,
You're assuming that they care.
> Having this graph burned into their minds might scare 'em into showing up on days they otherwise would not have.
Do you really think that seeing that graph will keep them from engaging in short-term thinking? Wowsers.
The graph shows one consequences of short-term thinking. However, they're surrounded by negative consequences of short-term thinking and still they continue.
> Cigarettes are chemically addictive
That's not the only effect. It may not even be the strongest.
And it isn't true of starting smokers. They also know what smoking will do for them, but yet they start.