I can’t believe I’m saying this, and I’m aware of the potential for innuendo here, but I am going to have to ask what you mean by “pegging” a PSU.
A 65W PSU can supply at most 65W, but it doesn’t “draw 65 watts regardless”. It will draw less than max power if it is using less.
Yes, indeed. I think we have the same understanding.
Pegging means the appliance is drawing the max amount of current. As a PC becomes more efficient, the PSU does not shrink. It just gives more calculations for the same energy drawn. But if it’s mostly at idle doing basic tasks like web browsing, there isn’t a notable consumption difference. A 65W PSU was typical two decades ago, and also still today.