Its not that bicycles need more tweaking, its that motor vehicles don't get enough.

If a motor vehicle's tires are low one just needs to push the gas a bit more and it takes a bit more fuel - a difference hardly any one will notice. A cyclist can feel the extra resistance from a soft tire and would rather take the time to keep tire inflated to keep the bike as efficient as possible.

I'd wager than there is a significantly higher percentage of under inflated regularly used motor vehicle tires than regularly used bicycle tires.

(all the above similar for transmission/drivetrain, suspension, alignment, etc.)

Al