A well thought out software architecture is indeed worth a lot. So a group of engineers that are able to actually make accurate architecture and decisions from the get go would help a lot. But the problem is requirement changes. And that's the core issue.

For something relatively set in stone like a car control system for ICE timing and whatnot, the requirement will not change by the fact that it is tied to another design which must also have been fixed beforehand and cannot be changed easily mid way willy nilly like software.

The engineer designing the engine must do a lot of administrative tasks again to make sure they pass every regulation under the sun when a change is made. We, the software guy does not have the equivalent of those barrier when a service requirement change. At most it is something about data privacy and security but that's about it. Everything else is fair game

A spec that’s more than a single page rarely survives initial contact with reality.