It's quite possible that he actually lost it or isn't doing it for some other reason. If it's him and he genuinely doesn't care about proving it, no one will ever know. Either way, it's intriguing.
When I was 10 years old or so I went on a random mac forum and posted that I was Steve Jobs and I had decided that Apple computers were worthless and everyone should just buy a PC. This has a similar feel to me (and I mostly use Macs today).
How did you manage to obtain Steve Jobs' real email? That seems to be the case. Whether it involved stealing the password, hijacking the domain, or something similar, the fact remains that he sent it from the real email.