I think engines and oil have improved to where you could go as long as you wanted on an engine if the oil, coolant, and such is maintained. There are very few engines that seem to fail with decent car these days. More and more cars use timing chains instead of belts so these will last a LONG time if you take car of the oil. Even cheap cars have gone to timing chains again.
I agree about the electronics. This stuff will fail before the engine and other major mechanical parts. Keep it as simple as possible.
Rust is the killer overall here. I have purchased pefectly good used engines cheap out of vehicles that were structurally coming apart. Someone here was mentioning that there is no point in using synthetic oil in a car that doesnât require it when the engine will outlast the rest of the car anyway. That being said, I still use synthetic but stock up when there are deals/rebates so I find it is actually cheaper to use synthetic by doing this.