In Ive's case, the British accent helps. Hearing him talk about his design decisions is captivating in the same way as David Attenborough narrating nature.
I'm not sure why the others don't seem to have as much of the latter, unless it's because they only managed the team that built the OS or the A4 or whatnot, instead of actually coding or designing it themselves.
Of course, Jobs doesn't actually do that either, but has always managed to talk as if he did.