Totally get it. My uncle's old truck is proof. You could fix half the engine with a wrench and a swear jar. Now a single sensor goes bad and the whole computer throws a fit. They don't build things to be fixed anymore, just replaced.
Ugh, tell me about it! I had the same thought last week when my car's engine light came on for something stupid. The repair guy basically said the whole system is designed to talk to one computer, so even a cheap part needs a crazy expensive scan to reset it. Feels like they make things confusing on purpose so you have to pay the dealer.