Jobs is cleverly using sample bias in Apple's favor for PR reasons here (though perhaps unintentionally). If someone emails Steve and doesn't hear back, they presumably don't write a blog post about it. Yet I suspect you're highly likely to hear about it when someone does get a reply, especially a phone call.

As a CEO you could probably make your customers think you care just by responding to .01% of emails or something like that. If all you have to do is call one guy every few weeks and tell him the same thing your underlings already told him to get this sort of coverage it's probably well worth the time.