If someone with a degree isn't able to cross their interview, what would make then think that someone without a degree would be able to do it ? Why would they risk spending on the interview where they think the candidate has even lesser chance ?
Nothing would make them think that and that's obvious so the real question is "why do they think that?" because the fact is there are a lot of great programmers that never got a degree.
The answer to the 2nd questions is to find someone who can actually do it. If you need a real world example look at Apple Computer.