Repair shop owners also don't enjoy work which is unnecessarily difficult.

Between rebuilding an engine and disassembling a bumper to replace a lightbulb most mechanics would genuinely rather be doing the lengthy but interesting work of rebuilding an engine than the lengthy and fucking boring task of disassembling a bumper to fix a lightbulb.

Moreover, even if a mechanic must charge you stupid amounts of labour cost to do a simple repair because it genuinely takes that much time, the customer might not come away with it thinking: "fuck, I bought a dumb car which is expensive to repair", they might instead come away with it thinking: "all these mechanics, quoting ridiculous prices to fix a light bulb, they must all be scammers".