Comment by mindcrime

You're not wrong. But still, a lot of gadgets can be repaired with some knowledge and effort, even if you don't have a schematic. If one just knows, for example, that very many faults are power supply related, and knows that problems with capacitors and transistors are responsible for a lot of power supply problems, you can accomplish quite a bit.

But yes, if you are talking about replacing BGA packaged high-end chips in very complex devices, there's a threshold were it becomes very difficult. But even then, if we watch some of what the different folks on Youtube accomplish repairing smartphones, laptops, etc., we'll see that some of these guys can achieve some pretty impressive results even without fancy labs and complete schematics, etc. Not everything is repairable of course, but I don't think pursuing this path is exactly "tilting at windmills" either.