Imagine a scenario identical to the premise of CalBear's Anglo American Nazi War TL where the Reich has dominated Europe, defeated the USSR and achieved an indefinite state of peace/stalemate with the WAllies.
They now have all of the time/resources to transform Europe, specifically Eastern Europe into their twisted version of utopia with Generalplan Ost as their homicidal blueprint.
Generalplan Ost designated the vast majority of Slavs for elimination. 50% of Latvians, 75% of Lithuanians, 65% of Ukrainians, 75% of Belorussians, 80-85% of Poles, 50% of Estonians, and 75% of Russians over a scheduled 25-30 year period. This makes for a total of 100+ MILLION people marked for "removal" with the rest designated for use as slaves on German plantations in the East.
The primary method for this massive genocide was going to be extermination through labor/starvation. All Slavic cities would be torn down by their inhabitants brick by brick until no trace was left. The "excess" Slavic population would be worked to death in mines, factories, construction of fortifications, building the cities of Hitler's dreams and other projects while most of the rural population would be kept alive to serve as serfs on Aryan farms.
Given enough time could Germany have managed to carry their plan out, killing the majority of Slavs and enslaving the rest?
Or would it have been abandoned halfway due to difficulties or pragmatism?
I believe they could have pulled it off considering the death toll they achieved in a span of 6 years while busy at war with the most powerful nations on the planet on multiple fronts. Imagine how many they would have managed to kill if they had unhindered logistics, complete devotion to the task, the resources of an occupied Europe and had several DECADES to do so.
To kill that many over the span of 30 years isn't that difficult if you think about it. It would mean working to death/starving an annual amount of 3 to 4 million people. And knowing how insanely evil the Reich/Nazi Party was they could have done it in a cost effective and vicious manner. If there was one thing Nazi Germany excelled at it was killing.
It worked on a smaller scale in the concentration camps and industries where massive slave labor was used so why wouldn't it work on a larger scale with far more resources and far longer amount of time to do so?