The late 70’s and 80’s were a different time. All GM has was big burly vehicles with massive v8’s cause that’s what the people wanted
then bam emissions standards and fuel economy averages came out and forced GM to basically completely re engineer their entire line up all at once. That’s why badge engineering happened. Tiny shit cars with shit engines and transmission engineered all at once and they all got the same shit.
imports were way ahead of that game cause that was already their market and knew how to manage