As up to recent "non Apple consumer" I wasn't really aware of the scale of the problem. Now I remember my friend listening to her Mac Laptop while taking a bath. No, laptop did not fall in water, was merely sprayed by some water, but (as it seems it had been enough to lit its sensors) it stopped working. She went to "Geniuses/Genies" and was told only possibility was complete motherboard replacement with high replacement cost, effectively as usual - almost buying a new Mac. She went back home, dried it using hair fan, left it for half a day and everything was good.
My general conlusion on this case (and at what one can see on Louis Rossman and right to repair channel) is that they actually dont do in depth diagnostics, just en general what could be overall replaced, to drive customers off. Essentially that is doing no repair job at all, just massive replacements. So "quality of service" is easy on repair guys, heavy on users and massively overpaid. Very malicious practice. No real repair guy should give immediate verdicts, but leave it for few days for diagnostics and error diagnostics should be cheap and fair.
No real repairs in 20/21st century, just consumers "throw and replace". Similar with PeeCees and phones. But in past at least schematics were freely provided for knowledgeable electric engeeners and technicians.
It seems Apple lives "second profit life" of such repair services and now extended SSD prices on M1 class Macs
