What engineering innovation in the recent decades has enabled oil-lubricated internal combustion engines to not require warming up?

Much tighter electronic control of fuel, ignition and even cooling system combined with tighter tolerances and modern oil formulations. Wait for the cat to light off and the revs drop and then put it in gear and take it easy for the next couple of minutes of driving.

Getting rid of the internal combustion engine is the main one, but your point stands.