So you can Drive Like a ProWhy GMC charging more for there Yukons and Sierra’s over the Tahoes and Sliverado‘s with the same features and Tech. Is the dealership experience more upscale?

Really, the difference between Chevy and GMC is like the difference between Honda and Acura.
Years ago, GMC really was “professional grade” - they were the heavy truck and bus division of GM, Detroit Diesel and Allison also fell under GMC. The GMC logo was on the RTS series of transit buses before GM divested the bus division to Greyhound in New Mexico and eventually NovaBus in Canada.