The underlying assumption "general autonomous driving can be made much safer in a short timeframe [years]" is not granted. It may be that the first option could

The underlying assumption "general autonomous driving can be made much safer in a short timeframe [years]" is not granted. It may be that the first option could have a death toll higher than what it would prevent - but the thing is, we don't know, it's an unknown, an assumption "it will be much better once everybody drinks the koolaid."