It looks a little different when you factor in other debt.
Business, household and financial sector debt was plummeting while US debt was going up in the thirties. The overall debt burden was falling all the way until the fifties. When US gov debt peaked in 45, overall debt was still on a downward trajectory. Now all debt is parabolic.
It's not as easy as saying that we got out of it in the thirties so we can get out of it again.
This time there is a boatload more debt. And we can't leave out the fact that we were the low cost producer in the world economy in the forties. Not only low cost, but only major producer seeing as how europe was bombed to smithereens. Now we're not and we can't compete our way out of this debt.