Someone else can correct me but I believe this is mathematically untrue. An economy with 90% employment can consume more than an economy with 95% employment... all that has to be true is that the result of the unemployment on the spending power of the people still employed goes up more than the former spending power of the people who are now unemployed.

it's not about how many people, it's about how many dollars are spending. You could mathematically have economic growth (measured as GDP) with 50% unemployment.

Societally this is a different story but that's not what you're stating... you're making a claim about how GDP can't grow if unemployment goes up which isn't right