The average income in the U.S. is $26,036 (I don't know if the average is just of adults in their working age or over the total population. I'll assume for my math it's the total population). The national debt is $48 trillion, or $161,287 per man, woman and child.
That means if everyones income went to nothing but the debt, it would still take over 6 years to pay off.
And to think, under Clinton the debt was going down and paying it off in a reasonable amount of time seemed possible.