Following Occam's razor, perhaps it's that it's just cheaper?
"The monthly pay ranking of German states is headed by Hamburg with 3,619 euros, followed by Baden-Württemberg with 3,546 euros and Hesse with 3,494 euros. The lowest salaries are received by employees in Mecklenburg-Western Pomerania with an average of 2,391 euros. Slightly more is earned in Thuringia with 2,459 euros and Saxony with 2,479 euros."[0]
[0] https://www.deutschland.de/en/topic/business/pay-in-germany-...