With all due respect, there is zero excuse to not do a live stream. EA, Sony, Nintendo, Microsoft, they all stream their press conferences from E3 to millions of people via dozens of websites and none of them are sitting on the half a trillion dollars that Apple is sitting on.
They could easily do it, the *only* logical explanation is that they don't want anyone to see them screw up.
Live streaming it would make the anticipation and excitement for their products palpable. They already have people lining up a day(s) in advance, they'd sell even more even faster if they live streamed it.
Absolutely no excuse not to live stream it.