This is absolute nonsense. As someone who has built computer systems and has been an avid overclocker for the better part of 30 years, i can say without any doubt that these components do physically change which is why a large number of people have noted over on overclock.net that their PCs can no longer run the same clock speeds as they did just a few years earlier without increases in voltages, and in some cases regardless of voltage. Of course your first reaction will be to blame this on heat, but that theory doesn't fly because people like myself have custom loop watercooling systems where the CPU, GPU, or voltage regulators are kept 30-50'c cooler than air cooled computers. And nobody here is claiming that these changes have such unpredictability that it would make the design and manufacturing of a product with a consistent resulting sound impossible. You implied that with the intent of showing your argument as the valid one, but the fact that modern PC's have features such as line load calibration, and individual variable voltage regulation to almost every component on a motherboard that is designed to maintain a PC's stability over years of use where capacitors change and degrade, and silicone chips lose efficiency through voltage leakage causing increased heat and thus requiring more voltage. I'm not saying this all would directly apply to audio amplifiers, but your analogy of implying it doesn't apply to computer electronics is patently false.