Earlier quoted context omitted.
There is for sure something about in-person interaction that cannot be replaced by any current technology. Alan Kay recently told me he thinks it's something biological. Our model just doesn't work well for people that can't move to the valley for 3 months. Remote work is good in many cases, but early-stage startup advising is not one of them.
There's evidence that babies acquire phonemes when "taught" in-person differently than via video: http://www.ted.com/talks/patricia_kuhl_the_linguistic_genius... (this topic starts at about 7m08s)
In a lot of ways, startups are like parenting I guess. Certainly parenting is another example of an activity that depends absolutely on physical presence :P