I think a lot of the answer is that hash functions last a while. SHA1 lasted about 30 years, and SHA2 seems like it will last at least as long. furthermore, eve

I think a lot of the answer is that hash functions last a while. SHA1 lasted about 30 years, and SHA2 seems like it will last at least as long. furthermore, even if SHA2 becomes broken, it's hard to imagine needing to move to more than 32 bytes.