j par said

Here's my theory on why they last longer..
think about being able to turn off the fuel injection and the ignition gets to burn those last bits of fuel before it shuts off. Then think of a carbureted car that shuts off the ignition and the Pistons are still going up and down sucking down the fuel and air on top of the cylinders which now at startup has washed the oil off..

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1. Overdrives. A engine turning 2200 rpm's vs 1600 rpm's @ 60 mph. That's 36,000 more revolutions in 1 hr. Think of all the hours to get to 100,000 miles.
2. Oils. Todays off the shelf oils are superior to yesterday oils (except for our flat tappet cams)
3. As J par mentioned, FI vs Carbs. FI runs the car so much cleaner.
4. Progression in the machining process. You didn't find Auto Gauges at the end of a CNC process 100% gauging every critical dimension of a machined part and feeding offsets back to the lathes.