Cars are much more expensive today than ever before, but they are also much more advanced.
If you built a 1990 car brand-new today I'll bet it would cost LESS than 1/4 of the median income.
However, you can't legally sell a new car today that's built to 1990 standards.
So how DO we measure price inflation in a product like this?
"Quality" has always been one of the most difficult things to measure and compare in price inflation.
That, my friend, is the job of the boys and girls at the Bureau of Labor Statistics. The job is arcane and difficult, as you have just noted. BUT, consider carefully who signs their paychecks. They all know which side their bread is buttered on, and they know that low inflation is politically more acceptable than high.
Every single time there is a choice to be made, they know how the calculation will come out and they choose the low inflation assumption rather than the high inflation one.
If you want your blood pressure to raise beyond control, Google "Shadow Government Statistics" and take a look at a better estimate of real inflation.