Until 1994, the year of the first software-only recall, maybe. Things have changed.

Heck, manufacturers were issuing service bulletins to fix the fuel maps in their cars in the 1980s.

It was not. Recalls have included software updates (sometimes via component replacement) since ECUs became common in the 1980s. Reverse engineering the binaries and flashing updated parameters is actually how ECU tuning used to be done.

But those cars are no longer competitive. There is only a marginal buyer group who wants to drive these "bricks", which would also unlikely pass the requirements set for new cars.