Who said anything about a Q50 base model? Base price does not equal base model.
I have been in both cars. I'm not pulling any of this out of thin air. None of it is unfounded. If that's narrow-minded to you, then awesome. I hope when you drive the SS it feels like a Cadillac to you, by whatever definition of Cadillac that is to you. That's all that matters is that you enjoy the car you buy.
The reality of the market is this - the Chevy SS is NOT a luxury car. Compared to a late 90s Q45? Hopefully so. Luxury car amenities of the 90s can be found in Sentras today. The Chevy SS is available as a new car today. Compared to today's cars on today's market with today's pricing and today's amenities, it's not. It's a non-luxury car on a non-luxury brand with non-luxury amenities and non-luxury interior quality by today's standards, new-for-new, pound-for-pound. That's not narrow-minded, that's fact.
Good luck with your car search.