The question is, what does "better" mean. It means that they tend to have a higher load at which they break down. That's better if we run the bike close to the thermal limits, but makes little or no difference under normal riding conditions.
Let's say an oil oil broke down at say 1000 units of lad and a modern oil break down at say 2000 units. That's great, but our bikes are running no where near the limit of the old oils under normal conditions. Let's say they run at 250 units at low speed and say 800 at high speed/heavy load. They would not normally fail even with old oil.
Where things get messy (pardon the pun) is where we run a 30 something year old bike on gas that isn't quite what it used to be and with ignition timing that maybe not 110% perfect for that gas, and now the loads are much higher - maybe up to 990 on our hypothetical scale.
So there is no doubt that a good modern oil offers a higher level of protection for the days that we need it. As for reducing oil output at low speeds, the better oil makes no difference unless the bike is running hotter than it's supposed to internally.
As to whether or not it's "better" to reduce oil output or not, clearly there are two opinions. Your mileage may vary
The logical deduction is that a so called better oil does not allow lower pump outputs UNLESS the motor is close to the limit. Under normal conditions it does not help.
