I disagree with the article.
There are two types of brake fade. Pad fade, and fluid fade.
Pad fade is extremely rare on bikes. Pad fade is when the pad material over heats and builds a gas barrier layer between the pads and the rotor. Pad fade the lever does not get soft. The brakes just seem to stop working as well
Fluid fade comes from having fluid that has too low a wet boiling point or air in the lines. As the temps rise the water in the fluid boils off and creates tiny air pockets which make the lever spongie and it to come back farther.
Modern brake line don't flex near as much as they used to. They are Kevlar lined which has nearly the same tensile strength as steel. Inside that Kevlar lining is the same hose liner as steel lines have.
The benefit that steel lines give you is they often have a smaller inside diameter which has less fluid and gives more feel if you are talented enough to utilize it. They are a bit tougher in a crash. And they may sink heat away a bit better.
The article acts as if the lines are just a rubber hose. They aren't. They have Kevlar webbing inside that does the same job the steel braiding does
Define "fluid is always fresh"???
If I were a betting man if bet your fade is almost assuredly due to either wet fluid, or incomplete bleeding. I have done a few articles on it. Especially with the pre-recall master the gsxr brakes are finicky to bleed but I've developed a technique that dn near guarantees perfect bleeding. I have helped dozens if not hundreds of people cure what they thought was a bad master cylinder or other issue simply with a thorough and proper bleed
My write ups are in the "mods and how to" section. There are three of them. If you do all three your fade will almost guaranteed be gone.