I think you forgot that each private key can generate 2 addresses (compressed and uncompressed in legacy version), so I believe that you have to take this fact into account as well.
True. You're right, the average is 2**96.78 private keys / address.
Btw you always say h160 is always uniform.
But im scanning over 256 trilions keyspace in h160 prefix . several private key position / range , and the result is vary , some even differ bout +10% 🤔.
You're analyzing a grain of sand and making assumptions about the entire beach.