Germans could see the writing on the wall. They had least holdings and alliances in Romania, Bulgaria, Finland, Belgium, Luxembourg, France and half of Holland.
German war production was also attenuated. German factories produced 35,000 rounds of heavy artillery in December 1944, but that same time slot showed forces fired 70,000 rounds. From January through October, the German produced just 46000 new military vehicles while the Wehrmacht lost 118,000. The Allied bombardment of the Ruhr valley halved German steel production. Mountains of coal could not be moved to market because shipping infrastructure was badly damaged and they could supply areas that desperately needed this.
Germans were ordered to work 60 hour weeks to make up for the loss of production. Holidays were eliminated. In tank factories the work week was 72 hours mandatory and the Heroes of Nationalist Socialist Labor were given more food and vitamins and vacations in the Tyrol as incentives. People who were defeatist could be shot and the rest of the massive labor requirements came from slaves.
Source: The Guns at Last Light by Rick Atkinson