Exactly. Cars get scrapped because the part costs $W, you can't run a compliant business for less than $X, the tech needs to be paid $Y, the service manual sub

Exactly. Cars get scrapped because the part costs $W, you can't run a compliant business for less than $X, the tech needs to be paid $Y, the service manual subscriptions cost $Z and they all add up to a number greater than what a 2002 Cavalier is worth. An under the table side gig mechanic can perform many more jobs in an economically viable manner because the fixed costs are so much less.