Earlier quoted context omitted.
They were going after key people like academics, engineers, doctors, artists first.
Yeah the Nazis had future plans for Poland. The idea was to make the entire country into illiterate slaves. A lot of people don't know that although what the Nazis did was obviously terrible it was nothing compared to what they wanted to do. Poland survived 60 years of communism. It would not have survived national socialism.
There was a version which considered leaving 15%-20% of the Polish population to be slaves, but "In 1941, the German leadership decided to destroy the Polish nation completely, and in 15–20 years the Polish state under German occupation was to be fully cleared of any ethnic Poles and settled by German colonists.[16]: 32 A majority of them, now deprived of their leaders and most of their intelligentsia (through mass murder, destruction of culture, banning education above the absolutely basic level, and kidnapping of children for Germanization), would have to be deported to regions in the East and scattered over as wide an area of Western Siberia as possible. According to the plan, this would result in their assimilation by the local populations, which would cause the Poles to vanish as a nation.[46]"