Hours worked are pretty low compared to other European states even if you factor in a large part time component. I don't think increasing hours would increase productivity anymore.
There is also a darker side of course with a lot of minimum wage jobs or people working long hours while still being dependent on the state. Even for employees of the same company the income can be quite unequal. Compare development or engineering with production or logistics for example.
A lot of very basic, work-intensive or energy-intensive work has left Germany over the last 30y, but the companies make a killing of value-added manufacturing.
Also, not least due to unification, till a couple of years ago, German wages were very stagnant, so it wasn't that great a country for industrial workers, paywise.