Why dont cars have cabin noise ratings?

Tires have noise ratings

if you can record something as varaible as MPG for an engine, noise in a cabin is definitely possible

I dont see why there can't be a standardised test at say 30mph and 70mpg for noise inside a car

There could be a test in a room, to measure engine noise, then a test on a standardised road to account for wind noise.

Maybe I'm getting old / boring, but how quiet a car is on a cruise is as important as things like the suspension, mpg etc.