Variable valve timing is becoming a standard system on most late-model engines because it offers higher performance from a smaller displacement engine at higher rpms. Oil plays a larger role in VVT systems. They need engine oil not only for lubrication, but also to actuate the camshafts to change the profile of the lobes.
They say an engine is only as reliable as its weakest link. The connecting rods that join the pistons with the crank can be a strong link or a weak link depending on the rods that are used. Most late model stock engines use powder metal rods. They are inexpensive to manufacture, require minimal machining to finish and are adequate for stock power levels and normal driving.