Actually, that latter is a trend to make things more compact. The engine compartment of my current car, which has the very requirement that you mention, has no

Actually, that latter is a trend to make things more compact. The engine compartment of my current car, which has the very requirement that you mention, has nowhere near the amount of extra unused volume as the engine compartment of the car that I was driving a couple of decades ago had, permitting access to many components without other components being in the way. The engine compartment is also, itself, smaller overall.