Beware of attempting to extract patterns from self-reported in-person interview failures. Most people who fail at the BigCo interviews I'm familiar with are getting bad reviews for:

poor communication, not making sure they understand the problem, not testing their solution, not being willing or able to explain their thought process, being unable to answer "I don't know" when pressed.

Occasionally there's someone who claims to know something and very clearly doesn't.

Phone screens generally filter out most of the people who know no data structures or algorithms.

Of course, every hiring process is different, so there's some variation within and across companies, but I think a lot of geeks think they screwed up the tech when they really screwed up the communication.