It's not a spectrum, instead a duality. An engine is an asset, yet it needs maintenance. Because software is soft, existing assets become yet more stuff to understand, more stuff to fix and keep in sync.
Compare for example a building made of stacked stone, brick, concrete, or modular carbon sheets on rebar
Another example, 100 hotel rooms, rearrange the layout and it's 101 things to do.
The analogies still fail, software updates are more akin to welding an airplane on to a car attached to a subway train. It's less, oh, we need to rework these weldzhere, it's often trying to make the software do something that is radically different. Like inserting a romance chapter into a mystery novel that starts as a chemistry how-to