Attempting to hide it somewhere else doesn't really help when your whole system is compromised. Salting+hashing isn't the answer to 'how to store passwords so no hacker can ever get them', it's the answer to 'how to store passwords so it would take a very very long time and a lot of resources for a hacker to ever get them'. It's designed like this to also allow easy authentication of users by simply performing the same process used originally. So the only real thing storing the salt somewhere else would accomplish is greater latency for authentication.