September is shaping up to be a strange month for automotive retail.

New-vehicle demand remains surprisingly resilient, yet the average monthly payment is projected to hit a September record of $821.

Nearly 14% of new-vehicle loans now stretch 84 months or longer, almost 30% of trade-ins have negative equity, and manufacturers are spending more on incentives to keep customers in the market.

Still, the industry is selling at roughly a 16 million annual pace.

So maybe the real question isn't why consumers keep accepting $800 car payments.

It's who is still buying new vehicles.

Cox Automotive says today's new-car buyer is increasingly affluent. If higher-income households are supporting sales while more middle-income consumers migrate toward used vehicles, keep their existing cars longer or leave the market entirely, headline sales numbers may be hiding a major structural change.

Can a healthy new-car market remain healthy if the addressable customer base keeps getting wealthier and smaller?