The difficulty is, you don't know the 100 thousand number is lower than the 10-5 million number in advance. An estimate can be made, but humans have a
not unreasonable status quo bias in case like that. Come to think of it, status quo bias on risk is the opposite of the planning fallacy.
That is, without proof the new way will be safer in future by a specific proportion, how many excess deaths can the ethics committee sign off?
(You can make a similar, better founded argument for mass train transit. It is about 10 times safer than driving per passenger mile. So, reductions in safety that moves people from car commuting to train commuting (I imagine safety is expensive and cheaper transit would be more popular) might be worth it. No-one seems to advocate them though.)
That is, without proof the new way will be safer in future by a specific proportion, how many excess deaths can the ethics committee sign off?
(You can make a similar, better founded argument for mass train transit. It is about 10 times safer than driving per passenger mile. So, reductions in safety that moves people from car commuting to train commuting (I imagine safety is expensive and cheaper transit would be more popular) might be worth it. No-one seems to advocate them though.)