All of the above are big factors in the differences. Someone covered my point but let me take it a step farther.
The best lubrication protection you'll get is by creating a wedge of oil between the rod bearing and the crank. This is done with say 40lbs of oil pressure, which when the piston blows downward to move the crank, it maintains the wedge of oil, kinda like a hydraulic effect, piston/ bearing pushes oil-- oil pushes crank.
Now, at idle, say 28lbs of oil pressure exists at the light. When you get on the gas, oil has to be pumped up to the 40lbs to the bearings. Here's what I'm seeing.. oil pump immediately jumps to 40lbs of pressure between the oil filter and the pump(still have 28lbs at the rod bearings to the filter)... now depending on the filters ability to allow flow, oil has to pass through/by the filter to get to the rod bearings to increase the oil wedge(40lbs) at the rod bearing. All the while, as the oil is traveling to the bearings, you are effectively shearing the oil wedge as it isn't completely up to pressure yet. So, instead of using the oil to push down on the crank, the oil is only coating the bearing and this is when the barrier additive such as moly comes into play for the last line of defense for engine protection. Now, this all happens so fast that it doesn't seem like much but after a constant stop and go situation, the oil is sheared more than on the hwy where it maintains that constant wedge. Add to that, the load factors of moving a car from a dead stop vers a car already moving increases the demand of load to the bearing where the oil pressure is under it's norm. So, here it is, heavier load, less oil, causes more wear and more heat. Less load, more oil, causes less stress on the oil and less heat, less oil shearing, and less wear metals due to the shearing. Coupled with the idle time/ gas/blow by as pointed out earlier.