I’ve been posting on this very topic for a couple months, so I’d like to address a couple points that I have addressed in the past.
A quick calculation suggests that output is not linear. The first graph in the OP’s cite is industrial production (not manufacturing output), but comparing the output from the bottom of the current recession to the peak at the beginning of 1970 we can easily see that industrial output has more then doubled. However, population has only increased by ~50%. Then industrial production per capita has increased by about 40% in that time (more, now that we’re in recovery). A post of mine from September (below) shows that manufacturing output per capita rose by a third or so within the same time frame.
Another old post of mine, this time from January, is below. It shows that 10 of the 11 durable goods categories reached their all-time peak output in the last decade. Five of those reached their peak just prior to the current recession.