I'm calling bs for the author painting with a broad brush.
And yes, YMMV.
in good weather if you overinflate by 30-35%, you will see noticeable mileage improvement. just don’t drive rough on your tires - peeling out, skidding, avoid rough roads when possible, and check how the tread is doing every week. in wintertime don’t overinflate.
and anyone can use better lubricants. make sure engine air filter is replaced yearly or more if in dusty climates.
My wife and I both have 2008 Chevy Equinox SUVs. I keep gasoline/mileage logs. Both of these traditionally have gotten from 5% to 10% better mileage than shown on the sticker, and on trips on the interstate, up to 20% better.
I’ve found that they get better mileage at 70 to 80 mph than they do at 55. I think it has to do with the overdrive and the lack of need for acceleration on the interstate, not to mention it’s normally my foot on the pedal taking advantage of the ups and downs of the road, rather than the tendency of the cruise control to accelerate up grades when I’m willing to accelerate downgrade and drop off about 3 to 5 mph going upgrade. No, I don’t create traffic queue behind me. By the way, both vehicles are 6 cylinder automatics, and we get from 21 to 22 mph city driving, up to 25 on the road.
So regulatory capture is real?
Our 2012 Hyundai Elantra does not get close to the mileage as it was stated on the window sticker. The absolute best highway mileage I have ever achieved with this car was 36.9, it was suppose to get up to 40 ... It averages more like 33-34 mpg on the highway, and that is driving with a light foot. The little mpg calculator on the dash always reads 2-4 mpg over what it actually gets.
We now get a small refund from Hyundai for the rest of the years we own the car because they got sued for cheating on their mpg numbers. We very well may not have bought the car if we knew the real story upfront.