If you fill a glass with water, it's the same amount of water whether you drip it in slowly, or fill the glass in a few big pours spaced out in time. Dripping continuously vs several big pours does not have any effect on how fast water evaporates out of the glass. Whether water happens to be dripping into the glass at any given moment has no effect on the way water evaporates out. As long as there is some water in the glass, it's evaporating out at the same rate no matter what you do. The drops of water dripping in are not a magic blanket preventing evaporation.
Again, your analogy is flawed. Let’s try to fix it. Instead of water, let’s use a liquid that evaporates at a rate that is just slightly slower than the rate it drips in. Let’s start with the glass empty. With constant drips, the glass will slowly fill over time until it pours over the edge. It will take a while but eventually, the drips in will exceed the evaporation out. That’s the constant dragging of brakes scenario.
Now let’s pour in a large pour of this magic liquid and then let it sit for a while. The liquid is evaporating at the same rate as before but you aren’t adding any liquid in. The liquid level goes down. Now you pour in a bit more of the liquid and let it sit again. Same thing happens as before. If you carefully balance the input, the overall evaporation rate is higher than the overall liquid input and you end up with a glass that has less liquid in it than the constant input.
But we don’t need an analogy. We have the comparison of pulse braking vs constant braking. Even if the friction input is equivalent, constant input of heat results in a higher temperature of the rims than does large inputs of heat with significant periods of negative heat…i.e. radiant cooling. The result is a lower rim (or any other friction surface) temperature.
The heat input may not be equivalent, however. In the pulse braking method, the speed is faster and the time spent riding down a hill is lower. Less time results in less heat input. Additionally, the movement of the air over the rims is higher. This results in a higher exchange of heat and greater cooling than if the brakes are dragged constantly.
I don't know why you're so caught up in your magic blanket theory. It's simply plain wrong.
You call it a magic blanket. It isn’t. As for it being wrong, why don’t professional racers, who descent far faster and far longer than us mere mortals, stop in the middle of a downhill to let their brakes cool off? They pulse brake all the time. They brake hard before corners and stay off the brakes the rest of the time.