Around Germany and Greece there were other countries. They went by names like frugal four and PIIGS. They forced "austerity" and stricter working hours onto indebted countries to save their own banks.
The colours on this map show well that northern "productivity" is not about working hours, but about other topics that did not get addressed. Among these topics are also tax heavens (think the Netherlands) and money laundering (think Austria's special relationship with Russia).
So it was nothing more than poor political leadership without vision.
I didn't remember Greeks were accused of working too little hours. I thought the situation was blamed on corruption, tax evasion and ineptitude of the country's leaders.
Bullshit, it was blamed on spending all the money in drinks and women:
https://www.euronews.com/2017/03/22/calls-for-eurogroup-president-jeroen-dijsselbloem-to-resign-after-drinks-and
Unfortunately, I do remember some people misbehaving in such a manner. It weren't any official statements, but there were undertones accusing them of laziness.
Because the yellow press correctly figured they could sell "we are much better than those lazy foreigners". Nothing more, nothing less. As long as the average Bild reader gets to feel superior, all is well.