>average income has gone up
To that I would say there is likely a problem with average. I didn't see a break down of the data in your link, but admittedly its my lunch break and I didn't have the time to really dig for it either. But its entirely possible that some groups saw an outsized growth in wages while others didn't.
>The MSRP for a 2023 Mustang GT is $38,345
The MSRP of a Mustang GT is $42k before options https://shop.ford.com/configure/mustang/model/customize/ecob... The GT Premium is $47k