Some examples that come to mind: EGR (exaust gas reciculator) valves tend to get stuck in older vehicles, I know I've had a couple old beaters with this tech di

Some examples that come to mind: EGR (exaust gas reciculator) valves tend to get stuck in older vehicles, I know I've had a couple old beaters with this tech die and the solution on a budget is to close the pipe and ignore the check engine light. Diesel engines went from crude mechanical fuel pumps to higher pressure (better atomization) but then the $1500 pump becomes a wear item that needs a rebuild several times over the life of a vehicle, back pressure from DEF systems takes some efficiency away and I've seen claims that they significantly shorten the usually long life of a diesel engine. I'm all for electric that's less mechanically complex, we've been going towards it, but a lot of funny stops along the way (a 12v lead starter battery in a hybred car with a sizable EV battery pack etc.)