38 characters of ASCII gibberish (all 95 printable characters) gives you less than 2^256 possible passwords, and pretty much nobody uses a password with more entropy than that.
The problem is that you aren't just dealing with "any output from the first hashing algo", since passwords are going into that algo in the first place. A hashing algo can't add entropy, but collisions can reduce it.
An undetected I/O error is vastly more likely than even one accidental SHA-256 collision among billions of passwords. It's not quite literally impossible but I'd bet my car I never see it happen.
