[wat10000]

You're ignoring costs. If your microwave costs $100, then you're saying it's often ten cents to fix it. It is entirely possible that the bad component costs ten cents. But the cost of the repair is only ten cents if your time and travel is completely free. Let's say you have a well designed microwave that's easy to repair and a ten-cent component goes bad. How much do you think a repair shop in a wealthy country would have to charge for such a repair to keep the lights on? A 100% margin on that 10 cents won't even pay for the time the worker takes to say "hello" as you enter the shop. What's your optimistic estimate of how long it would take to replace such a component on a well designed unit? 10 minutes? Plus administrative overhead like collecting payment, probably storing the unit for a while until the customer picks it up, and dealing with "it was working fine until you touched it" idiots. And 10 minutes is extremely optimistic for something that's likely soldered (even highly repairable units are going to solder small stuff). How much does the repair person earn? Auto mechanics make maybe $25-30/hour in the US. Pad that significantly for their fully loaded cost to the business. If we assume it takes 20 minutes total, accounting for everything, you're looking at maybe $20 in actual costs for the business, not counting rent and equipment and such. You've already hit an appreciable portion of the cost of a new unit and that's with a lot of very generous assumptions.

Appliance repair might be a dying art but car repair is common. You can look there to see what simple tasks might actually cost. Something like installing new tires is probably comparable. It's not outrageously expensive but it's also not anything like ten cents.