Not that different...

actually its "number of wallets with balance"/2^160.

You don't need to find a specific private key, anyone will do that yields a public key that hashes to the BTC address.

A quick search shows there are a little over 30M addresses with a nonzero balance, which is just under 2^25.

That means the actual probability would be about 1/(2^135).

At a million hashes per second, that means you would likely find one after about 10^27 years.