Another factor that influences higher speed cruising comfort is exhaust noise ,in any vehicle if the exhaust is extremely loud it tends to make you think the engine is reving higher than if the sound is not so intrusive , I have noticed this in modified Cars and Trucks ,the GM two stroke diesel in my old International truck many years ago sounded like the pistons were swapping barrels at 2000rpm as it was firing every 2 strokes and I had the almost mandatory loud pipe on the truck

later on when I got into the bigger conventional diesels(Macks) and doing long hauls I kept the induction (twin snorkels) and exhaust stack noise down to a reasonable level , the same with motorcycles a loud Harley is a PITA to cruise at 130Kph for long periods and even worse to follow, I have followed noisy Rockets at highway speed and they sound like they are reving more than my relatively quiet Tors and Crossover equipped one